From 5f0ad3232bf1ebab020284895b61c5b8dea6f4d1 Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Sat, 26 Oct 2024 00:16:13 +0800 Subject: [PATCH 1/8] [InstCombine] Add pre-commit tests. NFC. --- .../InstCombine/known-phi-recurse.ll | 118 ++++++++++++++++++ 1 file changed, 118 insertions(+) diff --git a/llvm/test/Transforms/InstCombine/known-phi-recurse.ll b/llvm/test/Transforms/InstCombine/known-phi-recurse.ll index c2007d16ae93b..7604f3f0c1784 100644 --- a/llvm/test/Transforms/InstCombine/known-phi-recurse.ll +++ b/llvm/test/Transforms/InstCombine/known-phi-recurse.ll @@ -142,3 +142,121 @@ end: ret i32 %res } +define i32 @knownbits_phi_select_test1(ptr %p1, ptr %p2, i8 %x) { +; CHECK-LABEL: @knownbits_phi_select_test1( +; CHECK-NEXT: entry: +; CHECK-NEXT: br label [[LOOP:%.*]] +; CHECK: loop: +; CHECK-NEXT: [[INDVAR1:%.*]] = phi i8 [ [[LOAD2:%.*]], [[BB2:%.*]] ], [ [[X:%.*]], [[ENTRY:%.*]] ] +; CHECK-NEXT: [[INDVAR3:%.*]] = phi ptr [ [[INDVAR3_NEXT:%.*]], [[BB2]] ], [ [[P1:%.*]], [[ENTRY]] ] +; CHECK-NEXT: [[INDVAR4:%.*]] = phi i32 [ [[INDVAR4_NEXT:%.*]], [[BB2]] ], [ 0, [[ENTRY]] ] +; CHECK-NEXT: [[INDVAR5:%.*]] = phi i32 [ [[INDVAR5_NEXT:%.*]], [[BB2]] ], [ 0, [[ENTRY]] ] +; CHECK-NEXT: switch i8 [[INDVAR1]], label [[DEFAULT:%.*]] [ +; CHECK-NEXT: i8 0, label [[EXIT:%.*]] +; CHECK-NEXT: i8 59, label [[BB1:%.*]] +; CHECK-NEXT: i8 35, label [[BB1]] +; CHECK-NEXT: ] +; CHECK: default: +; CHECK-NEXT: [[EXT:%.*]] = sext i8 [[INDVAR1]] to i64 +; CHECK-NEXT: [[GEP1:%.*]] = getelementptr inbounds i16, ptr [[P2:%.*]], i64 [[EXT]] +; CHECK-NEXT: [[LOAD1:%.*]] = load i16, ptr [[GEP1]], align 2 +; CHECK-NEXT: [[MASK:%.*]] = and i16 [[LOAD1]], 8192 +; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i16 [[MASK]], 0 +; CHECK-NEXT: br i1 [[CMP1]], label [[BB2]], label [[BB1]] +; CHECK: bb1: +; CHECK-NEXT: [[CMP2:%.*]] = icmp ne i32 [[INDVAR4]], 0 +; CHECK-NEXT: [[CMP3:%.*]] = icmp ne i32 [[INDVAR5]], 0 +; CHECK-NEXT: [[OR_COND:%.*]] = select i1 [[CMP2]], i1 true, i1 [[CMP3]] +; CHECK-NEXT: br i1 [[OR_COND]], label [[BB2]], label [[EXIT]] +; CHECK: bb2: +; CHECK-NEXT: [[CMP4:%.*]] = icmp eq i8 [[INDVAR1]], 39 +; CHECK-NEXT: [[CMP5:%.*]] = icmp eq i32 [[INDVAR4]], 0 +; CHECK-NEXT: [[EXT2:%.*]] = zext i1 [[CMP5]] to i32 +; CHECK-NEXT: [[INDVAR4_NEXT]] = select i1 [[CMP4]], i32 [[EXT2]], i32 [[INDVAR4]] +; CHECK-NEXT: [[CMP6:%.*]] = icmp eq i8 [[INDVAR1]], 34 +; CHECK-NEXT: [[CMP7:%.*]] = icmp eq i32 [[INDVAR5]], 0 +; CHECK-NEXT: [[EXT3:%.*]] = zext i1 [[CMP7]] to i32 +; CHECK-NEXT: [[INDVAR5_NEXT]] = select i1 [[CMP6]], i32 [[EXT3]], i32 [[INDVAR5]] +; CHECK-NEXT: [[INDVAR3_NEXT]] = getelementptr inbounds i8, ptr [[INDVAR3]], i64 1 +; CHECK-NEXT: [[LOAD2]] = load i8, ptr [[INDVAR3_NEXT]], align 1 +; CHECK-NEXT: br label [[LOOP]] +; CHECK: exit: +; CHECK-NEXT: ret i32 [[INDVAR5]] +; +entry: + br label %loop + +loop: + %indvar1 = phi i8 [ %load2, %bb2 ], [ %x, %entry ] + %indvar2 = phi i64 [ %indvar2.next, %bb2 ], [ 0, %entry ] + %indvar3 = phi ptr [ %indvar3.next, %bb2 ], [ %p1, %entry ] + %indvar4 = phi i32 [ %indvar4.next, %bb2 ], [ 0, %entry ] + %indvar5 = phi i32 [ %indvar5.next, %bb2 ], [ 0, %entry ] + switch i8 %indvar1, label %default [ + i8 0, label %exit + i8 59, label %bb1 + i8 35, label %bb1 + ] + +default: + %ext = sext i8 %indvar1 to i64 + %gep1 = getelementptr inbounds i16, ptr %p2, i64 %ext + %load1 = load i16, ptr %gep1, align 2 + %mask = and i16 %load1, 8192 + %cmp1 = icmp eq i16 %mask, 0 + br i1 %cmp1, label %bb2, label %bb1 + +bb1: + %cmp2 = icmp ne i32 %indvar4, 0 + %cmp3 = icmp ne i32 %indvar5, 0 + %or.cond = select i1 %cmp2, i1 true, i1 %cmp3 + br i1 %or.cond, label %bb2, label %exit + +bb2: + %cmp4 = icmp eq i8 %indvar1, 39 + %cmp5 = icmp eq i32 %indvar4, 0 + %ext2 = zext i1 %cmp5 to i32 + %indvar4.next = select i1 %cmp4, i32 %ext2, i32 %indvar4 + %cmp6 = icmp eq i8 %indvar1, 34 + %cmp7 = icmp eq i32 %indvar5, 0 + %ext3 = zext i1 %cmp7 to i32 + %indvar5.next = select i1 %cmp6, i32 %ext3, i32 %indvar5 + %indvar3.next = getelementptr inbounds i8, ptr %indvar3, i64 1 + %indvar2.next = add i64 %indvar2, 1 + %load2 = load i8, ptr %indvar3.next, align 1 + br label %loop + +exit: + ret i32 %indvar5 +} + +define i8 @knownbits_phi_select_test2() { +; CHECK-LABEL: @knownbits_phi_select_test2( +; CHECK-NEXT: entry: +; CHECK-NEXT: br label [[LOOP:%.*]] +; CHECK: loop: +; CHECK-NEXT: [[INDVAR:%.*]] = phi i8 [ 0, [[ENTRY:%.*]] ], [ [[CONTAIN:%.*]], [[LOOP]] ] +; CHECK-NEXT: [[COND0:%.*]] = call i1 @cond() +; CHECK-NEXT: [[CONTAIN]] = select i1 [[COND0]], i8 1, i8 [[INDVAR]] +; CHECK-NEXT: [[COND1:%.*]] = call i1 @cond() +; CHECK-NEXT: br i1 [[COND1]], label [[EXIT:%.*]], label [[LOOP]] +; CHECK: exit: +; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[CONTAIN]], 1 +; CHECK-NEXT: ret i8 [[TMP0]] +; +entry: + br label %loop + +loop: + %indvar = phi i8 [ 0, %entry ], [ %contain, %loop ] + %cond0 = call i1 @cond() + %contain = select i1 %cond0, i8 1, i8 %indvar + %cond1 = call i1 @cond() + br i1 %cond1, label %exit, label %loop + +exit: + %bool = and i8 %contain, 1 + ret i8 %bool +} + +declare i1 @cond() From 015584b9b69e3f06e77f59f138cda5ba21b2bca3 Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Sat, 26 Oct 2024 00:23:35 +0800 Subject: [PATCH 2/8] [ValueTracking] Compute known bits from recursive select/phi --- llvm/lib/Analysis/ValueTracking.cpp | 7 +++++++ .../Transforms/InstCombine/known-phi-recurse.ll | 13 +++++-------- 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index e9ed8b3c862b5..e443488a56b3c 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -1566,6 +1566,13 @@ static void computeKnownBitsFromOperator(const Operator *I, // Skip direct self references. if (IncValue == P) continue; + // If the Use is a select of this phi, use the knownbit of the other + // operand to break the recursion. + Value *V; + if (match(IncValue, m_Select(m_Value(), m_Specific(P), m_Value(V))) || + match(IncValue, m_Select(m_Value(), m_Value(V), m_Specific(P)))) + IncValue = V; + // Change the context instruction to the "edge" that flows into the // phi. This is important because that is where the value is actually // "evaluated" even though it is used later somewhere else. (see also diff --git a/llvm/test/Transforms/InstCombine/known-phi-recurse.ll b/llvm/test/Transforms/InstCombine/known-phi-recurse.ll index 7604f3f0c1784..fd3728324b8ea 100644 --- a/llvm/test/Transforms/InstCombine/known-phi-recurse.ll +++ b/llvm/test/Transforms/InstCombine/known-phi-recurse.ll @@ -170,13 +170,11 @@ define i32 @knownbits_phi_select_test1(ptr %p1, ptr %p2, i8 %x) { ; CHECK-NEXT: br i1 [[OR_COND]], label [[BB2]], label [[EXIT]] ; CHECK: bb2: ; CHECK-NEXT: [[CMP4:%.*]] = icmp eq i8 [[INDVAR1]], 39 -; CHECK-NEXT: [[CMP5:%.*]] = icmp eq i32 [[INDVAR4]], 0 -; CHECK-NEXT: [[EXT2:%.*]] = zext i1 [[CMP5]] to i32 -; CHECK-NEXT: [[INDVAR4_NEXT]] = select i1 [[CMP4]], i32 [[EXT2]], i32 [[INDVAR4]] +; CHECK-NEXT: [[EXT2:%.*]] = zext i1 [[CMP4]] to i32 +; CHECK-NEXT: [[INDVAR4_NEXT]] = xor i32 [[INDVAR4]], [[EXT2]] ; CHECK-NEXT: [[CMP6:%.*]] = icmp eq i8 [[INDVAR1]], 34 -; CHECK-NEXT: [[CMP7:%.*]] = icmp eq i32 [[INDVAR5]], 0 -; CHECK-NEXT: [[EXT3:%.*]] = zext i1 [[CMP7]] to i32 -; CHECK-NEXT: [[INDVAR5_NEXT]] = select i1 [[CMP6]], i32 [[EXT3]], i32 [[INDVAR5]] +; CHECK-NEXT: [[EXT3:%.*]] = zext i1 [[CMP6]] to i32 +; CHECK-NEXT: [[INDVAR5_NEXT]] = xor i32 [[INDVAR5]], [[EXT3]] ; CHECK-NEXT: [[INDVAR3_NEXT]] = getelementptr inbounds i8, ptr [[INDVAR3]], i64 1 ; CHECK-NEXT: [[LOAD2]] = load i8, ptr [[INDVAR3_NEXT]], align 1 ; CHECK-NEXT: br label [[LOOP]] @@ -241,8 +239,7 @@ define i8 @knownbits_phi_select_test2() { ; CHECK-NEXT: [[COND1:%.*]] = call i1 @cond() ; CHECK-NEXT: br i1 [[COND1]], label [[EXIT:%.*]], label [[LOOP]] ; CHECK: exit: -; CHECK-NEXT: [[TMP0:%.*]] = and i8 [[CONTAIN]], 1 -; CHECK-NEXT: ret i8 [[TMP0]] +; CHECK-NEXT: ret i8 [[CONTAIN]] ; entry: br label %loop From b66b3ca6808e0485f349009447584effc27488d2 Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Sat, 26 Oct 2024 16:53:57 +0800 Subject: [PATCH 3/8] [ValueTracking] Increase recursion depth. NFC. --- llvm/lib/Analysis/ValueTracking.cpp | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index e443488a56b3c..d04884a2464bc 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -1568,10 +1568,13 @@ static void computeKnownBitsFromOperator(const Operator *I, // If the Use is a select of this phi, use the knownbit of the other // operand to break the recursion. + unsigned IncDepth = MaxAnalysisRecursionDepth - 1; Value *V; if (match(IncValue, m_Select(m_Value(), m_Specific(P), m_Value(V))) || - match(IncValue, m_Select(m_Value(), m_Value(V), m_Specific(P)))) + match(IncValue, m_Select(m_Value(), m_Value(V), m_Specific(P)))) { IncValue = V; + IncDepth = Depth + 1; + } // Change the context instruction to the "edge" that flows into the // phi. This is important because that is where the value is actually @@ -1586,8 +1589,7 @@ static void computeKnownBitsFromOperator(const Operator *I, // want to waste time spinning around in loops. // TODO: See if we can base recursion limiter on number of incoming phi // edges so we don't overly clamp analysis. - computeKnownBits(IncValue, DemandedElts, Known2, - MaxAnalysisRecursionDepth - 1, RecQ); + computeKnownBits(IncValue, DemandedElts, Known2, IncDepth, RecQ); // See if we can further use a conditional branch into the phi // to help us determine the range of the value. From d990febe06a684509c77df642ce986f65b0faed9 Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Sat, 26 Oct 2024 20:06:36 +0800 Subject: [PATCH 4/8] [ValueTracking] Adjust comments. NFC. --- llvm/lib/Analysis/ValueTracking.cpp | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index d04884a2464bc..bff2acb0f33c1 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -1566,9 +1566,14 @@ static void computeKnownBitsFromOperator(const Operator *I, // Skip direct self references. if (IncValue == P) continue; + // Recurse, but cap the recursion to one level, because we don't + // want to waste time spinning around in loops. + // TODO: See if we can base recursion limiter on number of incoming phi + // edges so we don't overly clamp analysis. + unsigned IncDepth = MaxAnalysisRecursionDepth - 1; + // If the Use is a select of this phi, use the knownbit of the other // operand to break the recursion. - unsigned IncDepth = MaxAnalysisRecursionDepth - 1; Value *V; if (match(IncValue, m_Select(m_Value(), m_Specific(P), m_Value(V))) || match(IncValue, m_Select(m_Value(), m_Value(V), m_Specific(P)))) { @@ -1584,11 +1589,6 @@ static void computeKnownBitsFromOperator(const Operator *I, RecQ.CxtI = P->getIncomingBlock(u)->getTerminator(); Known2 = KnownBits(BitWidth); - - // Recurse, but cap the recursion to one level, because we don't - // want to waste time spinning around in loops. - // TODO: See if we can base recursion limiter on number of incoming phi - // edges so we don't overly clamp analysis. computeKnownBits(IncValue, DemandedElts, Known2, IncDepth, RecQ); // See if we can further use a conditional branch into the phi From 5751edbea615bf41c0aa86f4366afcf04c2373cc Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Sat, 26 Oct 2024 20:36:39 +0800 Subject: [PATCH 5/8] [ValueTracking] Adjust known bits from select's condition --- llvm/lib/Analysis/ValueTracking.cpp | 13 +++++-- .../X86/2012-01-10-UndefExceptionEdge.ll | 39 ++++++++----------- .../Transforms/InstCombine/cast-mul-select.ll | 20 +++------- 3 files changed, 31 insertions(+), 41 deletions(-) diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index bff2acb0f33c1..6baecdb63456f 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -1574,11 +1574,13 @@ static void computeKnownBitsFromOperator(const Operator *I, // If the Use is a select of this phi, use the knownbit of the other // operand to break the recursion. - Value *V; - if (match(IncValue, m_Select(m_Value(), m_Specific(P), m_Value(V))) || - match(IncValue, m_Select(m_Value(), m_Value(V), m_Specific(P)))) { - IncValue = V; + Value *IncCond = nullptr; + bool InvertIncCond = false; + if (auto *SI = dyn_cast(IncValue)) { + InvertIncCond = SI->getTrueValue() == P; + IncValue = InvertIncCond ? SI->getFalseValue() : SI->getTrueValue(); IncDepth = Depth + 1; + IncCond = SI->getCondition(); } // Change the context instruction to the "edge" that flows into the @@ -1590,6 +1592,9 @@ static void computeKnownBitsFromOperator(const Operator *I, Known2 = KnownBits(BitWidth); computeKnownBits(IncValue, DemandedElts, Known2, IncDepth, RecQ); + if (IncCond) + adjustKnownBitsForSelectArm(Known2, IncCond, IncValue, InvertIncCond, + Depth, RecQ); // See if we can further use a conditional branch into the phi // to help us determine the range of the value. diff --git a/llvm/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll b/llvm/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll index 1962ddebc2115..01a8111ebe096 100644 --- a/llvm/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll +++ b/llvm/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll @@ -29,32 +29,29 @@ define void @f(ptr nocapture %arg, ptr nocapture %arg1, ptr nocapture %arg2, ptr ; CHECK-NEXT: pushl %ebx ; CHECK-NEXT: pushl %edi ; CHECK-NEXT: pushl %esi -; CHECK-NEXT: subl $28, %esp +; CHECK-NEXT: subl $12, %esp ; CHECK-NEXT: .cfi_offset %esi, -20 ; CHECK-NEXT: .cfi_offset %edi, -16 ; CHECK-NEXT: .cfi_offset %ebx, -12 ; CHECK-NEXT: xorl %eax, %eax -; CHECK-NEXT: xorl %edi, %edi ; CHECK-NEXT: testb %al, %al ; CHECK-NEXT: Ltmp0: -; CHECK-NEXT: ## implicit-def: $ebx +; CHECK-NEXT: ## implicit-def: $edi ; CHECK-NEXT: calll __Znam ; CHECK-NEXT: Ltmp1: ; CHECK-NEXT: ## %bb.1: ## %bb11 ; CHECK-NEXT: movl %eax, %esi -; CHECK-NEXT: movb $1, %al -; CHECK-NEXT: testb %al, %al +; CHECK-NEXT: movb $1, %bl +; CHECK-NEXT: testb %bl, %bl ; CHECK-NEXT: jne LBB0_2 ; CHECK-NEXT: ## %bb.7: ## %bb31 -; CHECK-NEXT: ## implicit-def: $eax -; CHECK-NEXT: ## kill: killed $eax +; CHECK-NEXT: ## implicit-def: $edi ; CHECK-NEXT: LBB0_8: ## %bb38 ; CHECK-NEXT: ## =>This Loop Header: Depth=1 ; CHECK-NEXT: ## Child Loop BB0_13 Depth 2 ; CHECK-NEXT: ## Child Loop BB0_16 Depth 3 ; CHECK-NEXT: ## Child Loop BB0_21 Depth 2 -; CHECK-NEXT: movb $1, %al -; CHECK-NEXT: testb %al, %al +; CHECK-NEXT: testb %bl, %bl ; CHECK-NEXT: jne LBB0_9 ; CHECK-NEXT: ## %bb.10: ## %bb41 ; CHECK-NEXT: ## in Loop: Header=BB0_8 Depth=1 @@ -78,8 +75,7 @@ define void @f(ptr nocapture %arg, ptr nocapture %arg1, ptr nocapture %arg2, ptr ; CHECK-NEXT: ## Parent Loop BB0_8 Depth=1 ; CHECK-NEXT: ## => This Loop Header: Depth=2 ; CHECK-NEXT: ## Child Loop BB0_16 Depth 3 -; CHECK-NEXT: movb $1, %cl -; CHECK-NEXT: testb %cl, %cl +; CHECK-NEXT: testb %bl, %bl ; CHECK-NEXT: jne LBB0_19 ; CHECK-NEXT: ## %bb.14: ## %bb48 ; CHECK-NEXT: ## in Loop: Header=BB0_13 Depth=2 @@ -88,14 +84,13 @@ define void @f(ptr nocapture %arg, ptr nocapture %arg1, ptr nocapture %arg2, ptr ; CHECK-NEXT: ## in Loop: Header=BB0_13 Depth=2 ; CHECK-NEXT: xorl %ecx, %ecx ; CHECK-NEXT: movl %esi, %edx -; CHECK-NEXT: movl %edi, %ebx ; CHECK-NEXT: LBB0_16: ## %bb49 ; CHECK-NEXT: ## Parent Loop BB0_8 Depth=1 ; CHECK-NEXT: ## Parent Loop BB0_13 Depth=2 ; CHECK-NEXT: ## => This Inner Loop Header: Depth=3 ; CHECK-NEXT: incl %ecx ; CHECK-NEXT: addl $4, %edx -; CHECK-NEXT: decl %ebx +; CHECK-NEXT: testb %bl, %bl ; CHECK-NEXT: jne LBB0_16 ; CHECK-NEXT: LBB0_17: ## %bb57 ; CHECK-NEXT: ## in Loop: Header=BB0_13 Depth=2 @@ -107,33 +102,31 @@ define void @f(ptr nocapture %arg, ptr nocapture %arg1, ptr nocapture %arg2, ptr ; CHECK-NEXT: movl %eax, {{[0-9]+}}(%esp) ; CHECK-NEXT: movl $0, (%esp) ; CHECK-NEXT: calll ___bzero -; CHECK-NEXT: movb $1, %al -; CHECK-NEXT: testb %al, %al +; CHECK-NEXT: testb %bl, %bl ; CHECK-NEXT: jne LBB0_22 ; CHECK-NEXT: ## %bb.20: ## %bb61.preheader ; CHECK-NEXT: ## in Loop: Header=BB0_8 Depth=1 ; CHECK-NEXT: movl %esi, %eax -; CHECK-NEXT: movl %edi, %ecx ; CHECK-NEXT: LBB0_21: ## %bb61 ; CHECK-NEXT: ## Parent Loop BB0_8 Depth=1 ; CHECK-NEXT: ## => This Inner Loop Header: Depth=2 ; CHECK-NEXT: movl $0, (%eax) ; CHECK-NEXT: addl $4, %eax -; CHECK-NEXT: decl %ecx +; CHECK-NEXT: testb %bl, %bl ; CHECK-NEXT: jne LBB0_21 ; CHECK-NEXT: LBB0_22: ## %bb67 ; CHECK-NEXT: ## in Loop: Header=BB0_8 Depth=1 -; CHECK-NEXT: decl {{[-0-9]+}}(%e{{[sb]}}p) ## 4-byte Folded Spill +; CHECK-NEXT: decl %edi ; CHECK-NEXT: jmp LBB0_8 ; CHECK-NEXT: LBB0_18: ## %bb43 ; CHECK-NEXT: Ltmp5: -; CHECK-NEXT: movl %esi, %ebx +; CHECK-NEXT: movl %esi, %edi ; CHECK-NEXT: calll _OnOverFlow ; CHECK-NEXT: Ltmp6: ; CHECK-NEXT: jmp LBB0_3 ; CHECK-NEXT: LBB0_2: ## %bb29 ; CHECK-NEXT: Ltmp7: -; CHECK-NEXT: movl %esi, %ebx +; CHECK-NEXT: movl %esi, %edi ; CHECK-NEXT: calll _OnOverFlow ; CHECK-NEXT: Ltmp8: ; CHECK-NEXT: LBB0_3: ## %bb30 @@ -141,10 +134,10 @@ define void @f(ptr nocapture %arg, ptr nocapture %arg1, ptr nocapture %arg2, ptr ; CHECK-NEXT: LBB0_4: ## %bb20.loopexit ; CHECK-NEXT: Ltmp4: ; CHECK-NEXT: LBB0_9: -; CHECK-NEXT: movl %esi, %ebx +; CHECK-NEXT: movl %esi, %edi ; CHECK-NEXT: LBB0_6: ## %bb23 -; CHECK-NEXT: testl %ebx, %ebx -; CHECK-NEXT: addl $28, %esp +; CHECK-NEXT: testl %edi, %edi +; CHECK-NEXT: addl $12, %esp ; CHECK-NEXT: popl %esi ; CHECK-NEXT: popl %edi ; CHECK-NEXT: popl %ebx diff --git a/llvm/test/Transforms/InstCombine/cast-mul-select.ll b/llvm/test/Transforms/InstCombine/cast-mul-select.ll index 6eb3a8c0a2049..0c3a80dd247e9 100644 --- a/llvm/test/Transforms/InstCombine/cast-mul-select.ll +++ b/llvm/test/Transforms/InstCombine/cast-mul-select.ll @@ -182,8 +182,6 @@ define void @PR36225(i32 %a, i32 %b, i1 %c1, i3 %v1, i3 %v2) { ; CHECK: while.body: ; CHECK-NEXT: br i1 [[C1:%.*]], label [[FOR_BODY3_US:%.*]], label [[FOR_BODY3:%.*]] ; CHECK: for.body3.us: -; CHECK-NEXT: [[TOBOOL:%.*]] = icmp eq i32 [[B:%.*]], 0 -; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[TOBOOL]], i8 0, i8 4 ; CHECK-NEXT: switch i3 [[V1:%.*]], label [[EXIT:%.*]] [ ; CHECK-NEXT: i3 0, label [[FOR_END:%.*]] ; CHECK-NEXT: i3 -1, label [[FOR_END]] @@ -194,9 +192,7 @@ define void @PR36225(i32 %a, i32 %b, i1 %c1, i3 %v1, i3 %v2) { ; CHECK-NEXT: i3 -1, label [[FOR_END]] ; CHECK-NEXT: ] ; CHECK: for.end: -; CHECK-NEXT: [[H:%.*]] = phi i8 [ [[SPEC_SELECT]], [[FOR_BODY3_US]] ], [ [[SPEC_SELECT]], [[FOR_BODY3_US]] ], [ 0, [[FOR_BODY3]] ], [ 0, [[FOR_BODY3]] ] -; CHECK-NEXT: [[CONV:%.*]] = zext nneg i8 [[H]] to i32 -; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[A:%.*]], [[CONV]] +; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[A:%.*]], 0 ; CHECK-NEXT: br i1 [[CMP]], label [[EXIT]], label [[EXIT2:%.*]] ; CHECK: exit2: ; CHECK-NEXT: unreachable @@ -210,10 +206,8 @@ define void @PR36225(i32 %a, i32 %b, i1 %c1, i3 %v1, i3 %v2) { ; DBGINFO-NEXT: #dbg_value(i32 [[B:%.*]], [[META89:![0-9]+]], !DIExpression(DW_OP_lit0, DW_OP_eq, DW_OP_stack_value), [[META95:![0-9]+]]) ; DBGINFO-NEXT: br i1 [[C1:%.*]], label [[FOR_BODY3_US:%.*]], label [[FOR_BODY3:%.*]], !dbg [[DBG96:![0-9]+]] ; DBGINFO: for.body3.us: -; DBGINFO-NEXT: [[TOBOOL:%.*]] = icmp eq i32 [[B]], 0, !dbg [[META95]] -; DBGINFO-NEXT: #dbg_value(i1 [[TOBOOL]], [[META89]], !DIExpression(), [[META95]]) -; DBGINFO-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[TOBOOL]], i8 0, i8 4, !dbg [[DBG97:![0-9]+]] -; DBGINFO-NEXT: #dbg_value(i8 [[SPEC_SELECT]], [[META90:![0-9]+]], !DIExpression(), [[DBG97]]) +; DBGINFO-NEXT: #dbg_value(i32 [[B]], [[META89]], !DIExpression(DW_OP_lit0, DW_OP_eq, DW_OP_stack_value), [[META95]]) +; DBGINFO-NEXT: #dbg_value(i8 poison, [[META90:![0-9]+]], !DIExpression(), [[META97:![0-9]+]]) ; DBGINFO-NEXT: switch i3 [[V1:%.*]], label [[EXIT:%.*]] [ ; DBGINFO-NEXT: i3 0, label [[FOR_END:%.*]] ; DBGINFO-NEXT: i3 -1, label [[FOR_END]] @@ -224,11 +218,9 @@ define void @PR36225(i32 %a, i32 %b, i1 %c1, i3 %v1, i3 %v2) { ; DBGINFO-NEXT: i3 -1, label [[FOR_END]] ; DBGINFO-NEXT: ], !dbg [[DBG99:![0-9]+]] ; DBGINFO: for.end: -; DBGINFO-NEXT: [[H:%.*]] = phi i8 [ [[SPEC_SELECT]], [[FOR_BODY3_US]] ], [ [[SPEC_SELECT]], [[FOR_BODY3_US]] ], [ 0, [[FOR_BODY3]] ], [ 0, [[FOR_BODY3]] ], !dbg [[DBG100:![0-9]+]] -; DBGINFO-NEXT: #dbg_value(i8 [[H]], [[META91:![0-9]+]], !DIExpression(), [[DBG100]]) -; DBGINFO-NEXT: [[CONV:%.*]] = zext nneg i8 [[H]] to i32, !dbg [[DBG101:![0-9]+]] -; DBGINFO-NEXT: #dbg_value(i32 [[CONV]], [[META92:![0-9]+]], !DIExpression(), [[DBG101]]) -; DBGINFO-NEXT: [[CMP:%.*]] = icmp sgt i32 [[A:%.*]], [[CONV]], !dbg [[DBG102:![0-9]+]] +; DBGINFO-NEXT: #dbg_value(i8 poison, [[META91:![0-9]+]], !DIExpression(), [[META100:![0-9]+]]) +; DBGINFO-NEXT: #dbg_value(i8 0, [[META92:![0-9]+]], !DIExpression(DW_OP_LLVM_convert, 8, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_stack_value), [[META101:![0-9]+]]) +; DBGINFO-NEXT: [[CMP:%.*]] = icmp sgt i32 [[A:%.*]], 0, !dbg [[DBG102:![0-9]+]] ; DBGINFO-NEXT: #dbg_value(i1 [[CMP]], [[META93:![0-9]+]], !DIExpression(), [[DBG102]]) ; DBGINFO-NEXT: br i1 [[CMP]], label [[EXIT]], label [[EXIT2:%.*]], !dbg [[DBG103:![0-9]+]] ; DBGINFO: exit2: From a5567a2119cf783d482c9152ac958fb841f87d91 Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Sat, 26 Oct 2024 23:28:23 +0800 Subject: [PATCH 6/8] [ValueTracking] Fix depth --- llvm/lib/Analysis/ValueTracking.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index 6baecdb63456f..51e1a0c2b53de 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -1594,7 +1594,7 @@ static void computeKnownBitsFromOperator(const Operator *I, computeKnownBits(IncValue, DemandedElts, Known2, IncDepth, RecQ); if (IncCond) adjustKnownBitsForSelectArm(Known2, IncCond, IncValue, InvertIncCond, - Depth, RecQ); + IncDepth, RecQ); // See if we can further use a conditional branch into the phi // to help us determine the range of the value. From 51f9734f620cfd29ff7bcfee08ed986b77b3273a Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Sat, 26 Oct 2024 23:52:53 +0800 Subject: [PATCH 7/8] [ValueTracking] Fix miscompilation --- llvm/lib/Analysis/ValueTracking.cpp | 10 +++-- .../X86/2012-01-10-UndefExceptionEdge.ll | 39 +++++++++++-------- .../Transforms/InstCombine/cast-mul-select.ll | 20 +++++++--- 3 files changed, 43 insertions(+), 26 deletions(-) diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index 51e1a0c2b53de..354fbd2e5bc94 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -1577,10 +1577,12 @@ static void computeKnownBitsFromOperator(const Operator *I, Value *IncCond = nullptr; bool InvertIncCond = false; if (auto *SI = dyn_cast(IncValue)) { - InvertIncCond = SI->getTrueValue() == P; - IncValue = InvertIncCond ? SI->getFalseValue() : SI->getTrueValue(); - IncDepth = Depth + 1; - IncCond = SI->getCondition(); + if (SI->getTrueValue() == P || SI->getFalseValue() == P) { + InvertIncCond = SI->getTrueValue() == P; + IncValue = InvertIncCond ? SI->getFalseValue() : SI->getTrueValue(); + IncDepth = Depth + 1; + IncCond = SI->getCondition(); + } } // Change the context instruction to the "edge" that flows into the diff --git a/llvm/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll b/llvm/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll index 01a8111ebe096..1962ddebc2115 100644 --- a/llvm/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll +++ b/llvm/test/CodeGen/X86/2012-01-10-UndefExceptionEdge.ll @@ -29,29 +29,32 @@ define void @f(ptr nocapture %arg, ptr nocapture %arg1, ptr nocapture %arg2, ptr ; CHECK-NEXT: pushl %ebx ; CHECK-NEXT: pushl %edi ; CHECK-NEXT: pushl %esi -; CHECK-NEXT: subl $12, %esp +; CHECK-NEXT: subl $28, %esp ; CHECK-NEXT: .cfi_offset %esi, -20 ; CHECK-NEXT: .cfi_offset %edi, -16 ; CHECK-NEXT: .cfi_offset %ebx, -12 ; CHECK-NEXT: xorl %eax, %eax +; CHECK-NEXT: xorl %edi, %edi ; CHECK-NEXT: testb %al, %al ; CHECK-NEXT: Ltmp0: -; CHECK-NEXT: ## implicit-def: $edi +; CHECK-NEXT: ## implicit-def: $ebx ; CHECK-NEXT: calll __Znam ; CHECK-NEXT: Ltmp1: ; CHECK-NEXT: ## %bb.1: ## %bb11 ; CHECK-NEXT: movl %eax, %esi -; CHECK-NEXT: movb $1, %bl -; CHECK-NEXT: testb %bl, %bl +; CHECK-NEXT: movb $1, %al +; CHECK-NEXT: testb %al, %al ; CHECK-NEXT: jne LBB0_2 ; CHECK-NEXT: ## %bb.7: ## %bb31 -; CHECK-NEXT: ## implicit-def: $edi +; CHECK-NEXT: ## implicit-def: $eax +; CHECK-NEXT: ## kill: killed $eax ; CHECK-NEXT: LBB0_8: ## %bb38 ; CHECK-NEXT: ## =>This Loop Header: Depth=1 ; CHECK-NEXT: ## Child Loop BB0_13 Depth 2 ; CHECK-NEXT: ## Child Loop BB0_16 Depth 3 ; CHECK-NEXT: ## Child Loop BB0_21 Depth 2 -; CHECK-NEXT: testb %bl, %bl +; CHECK-NEXT: movb $1, %al +; CHECK-NEXT: testb %al, %al ; CHECK-NEXT: jne LBB0_9 ; CHECK-NEXT: ## %bb.10: ## %bb41 ; CHECK-NEXT: ## in Loop: Header=BB0_8 Depth=1 @@ -75,7 +78,8 @@ define void @f(ptr nocapture %arg, ptr nocapture %arg1, ptr nocapture %arg2, ptr ; CHECK-NEXT: ## Parent Loop BB0_8 Depth=1 ; CHECK-NEXT: ## => This Loop Header: Depth=2 ; CHECK-NEXT: ## Child Loop BB0_16 Depth 3 -; CHECK-NEXT: testb %bl, %bl +; CHECK-NEXT: movb $1, %cl +; CHECK-NEXT: testb %cl, %cl ; CHECK-NEXT: jne LBB0_19 ; CHECK-NEXT: ## %bb.14: ## %bb48 ; CHECK-NEXT: ## in Loop: Header=BB0_13 Depth=2 @@ -84,13 +88,14 @@ define void @f(ptr nocapture %arg, ptr nocapture %arg1, ptr nocapture %arg2, ptr ; CHECK-NEXT: ## in Loop: Header=BB0_13 Depth=2 ; CHECK-NEXT: xorl %ecx, %ecx ; CHECK-NEXT: movl %esi, %edx +; CHECK-NEXT: movl %edi, %ebx ; CHECK-NEXT: LBB0_16: ## %bb49 ; CHECK-NEXT: ## Parent Loop BB0_8 Depth=1 ; CHECK-NEXT: ## Parent Loop BB0_13 Depth=2 ; CHECK-NEXT: ## => This Inner Loop Header: Depth=3 ; CHECK-NEXT: incl %ecx ; CHECK-NEXT: addl $4, %edx -; CHECK-NEXT: testb %bl, %bl +; CHECK-NEXT: decl %ebx ; CHECK-NEXT: jne LBB0_16 ; CHECK-NEXT: LBB0_17: ## %bb57 ; CHECK-NEXT: ## in Loop: Header=BB0_13 Depth=2 @@ -102,31 +107,33 @@ define void @f(ptr nocapture %arg, ptr nocapture %arg1, ptr nocapture %arg2, ptr ; CHECK-NEXT: movl %eax, {{[0-9]+}}(%esp) ; CHECK-NEXT: movl $0, (%esp) ; CHECK-NEXT: calll ___bzero -; CHECK-NEXT: testb %bl, %bl +; CHECK-NEXT: movb $1, %al +; CHECK-NEXT: testb %al, %al ; CHECK-NEXT: jne LBB0_22 ; CHECK-NEXT: ## %bb.20: ## %bb61.preheader ; CHECK-NEXT: ## in Loop: Header=BB0_8 Depth=1 ; CHECK-NEXT: movl %esi, %eax +; CHECK-NEXT: movl %edi, %ecx ; CHECK-NEXT: LBB0_21: ## %bb61 ; CHECK-NEXT: ## Parent Loop BB0_8 Depth=1 ; CHECK-NEXT: ## => This Inner Loop Header: Depth=2 ; CHECK-NEXT: movl $0, (%eax) ; CHECK-NEXT: addl $4, %eax -; CHECK-NEXT: testb %bl, %bl +; CHECK-NEXT: decl %ecx ; CHECK-NEXT: jne LBB0_21 ; CHECK-NEXT: LBB0_22: ## %bb67 ; CHECK-NEXT: ## in Loop: Header=BB0_8 Depth=1 -; CHECK-NEXT: decl %edi +; CHECK-NEXT: decl {{[-0-9]+}}(%e{{[sb]}}p) ## 4-byte Folded Spill ; CHECK-NEXT: jmp LBB0_8 ; CHECK-NEXT: LBB0_18: ## %bb43 ; CHECK-NEXT: Ltmp5: -; CHECK-NEXT: movl %esi, %edi +; CHECK-NEXT: movl %esi, %ebx ; CHECK-NEXT: calll _OnOverFlow ; CHECK-NEXT: Ltmp6: ; CHECK-NEXT: jmp LBB0_3 ; CHECK-NEXT: LBB0_2: ## %bb29 ; CHECK-NEXT: Ltmp7: -; CHECK-NEXT: movl %esi, %edi +; CHECK-NEXT: movl %esi, %ebx ; CHECK-NEXT: calll _OnOverFlow ; CHECK-NEXT: Ltmp8: ; CHECK-NEXT: LBB0_3: ## %bb30 @@ -134,10 +141,10 @@ define void @f(ptr nocapture %arg, ptr nocapture %arg1, ptr nocapture %arg2, ptr ; CHECK-NEXT: LBB0_4: ## %bb20.loopexit ; CHECK-NEXT: Ltmp4: ; CHECK-NEXT: LBB0_9: -; CHECK-NEXT: movl %esi, %edi +; CHECK-NEXT: movl %esi, %ebx ; CHECK-NEXT: LBB0_6: ## %bb23 -; CHECK-NEXT: testl %edi, %edi -; CHECK-NEXT: addl $12, %esp +; CHECK-NEXT: testl %ebx, %ebx +; CHECK-NEXT: addl $28, %esp ; CHECK-NEXT: popl %esi ; CHECK-NEXT: popl %edi ; CHECK-NEXT: popl %ebx diff --git a/llvm/test/Transforms/InstCombine/cast-mul-select.ll b/llvm/test/Transforms/InstCombine/cast-mul-select.ll index 0c3a80dd247e9..6eb3a8c0a2049 100644 --- a/llvm/test/Transforms/InstCombine/cast-mul-select.ll +++ b/llvm/test/Transforms/InstCombine/cast-mul-select.ll @@ -182,6 +182,8 @@ define void @PR36225(i32 %a, i32 %b, i1 %c1, i3 %v1, i3 %v2) { ; CHECK: while.body: ; CHECK-NEXT: br i1 [[C1:%.*]], label [[FOR_BODY3_US:%.*]], label [[FOR_BODY3:%.*]] ; CHECK: for.body3.us: +; CHECK-NEXT: [[TOBOOL:%.*]] = icmp eq i32 [[B:%.*]], 0 +; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[TOBOOL]], i8 0, i8 4 ; CHECK-NEXT: switch i3 [[V1:%.*]], label [[EXIT:%.*]] [ ; CHECK-NEXT: i3 0, label [[FOR_END:%.*]] ; CHECK-NEXT: i3 -1, label [[FOR_END]] @@ -192,7 +194,9 @@ define void @PR36225(i32 %a, i32 %b, i1 %c1, i3 %v1, i3 %v2) { ; CHECK-NEXT: i3 -1, label [[FOR_END]] ; CHECK-NEXT: ] ; CHECK: for.end: -; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[A:%.*]], 0 +; CHECK-NEXT: [[H:%.*]] = phi i8 [ [[SPEC_SELECT]], [[FOR_BODY3_US]] ], [ [[SPEC_SELECT]], [[FOR_BODY3_US]] ], [ 0, [[FOR_BODY3]] ], [ 0, [[FOR_BODY3]] ] +; CHECK-NEXT: [[CONV:%.*]] = zext nneg i8 [[H]] to i32 +; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[A:%.*]], [[CONV]] ; CHECK-NEXT: br i1 [[CMP]], label [[EXIT]], label [[EXIT2:%.*]] ; CHECK: exit2: ; CHECK-NEXT: unreachable @@ -206,8 +210,10 @@ define void @PR36225(i32 %a, i32 %b, i1 %c1, i3 %v1, i3 %v2) { ; DBGINFO-NEXT: #dbg_value(i32 [[B:%.*]], [[META89:![0-9]+]], !DIExpression(DW_OP_lit0, DW_OP_eq, DW_OP_stack_value), [[META95:![0-9]+]]) ; DBGINFO-NEXT: br i1 [[C1:%.*]], label [[FOR_BODY3_US:%.*]], label [[FOR_BODY3:%.*]], !dbg [[DBG96:![0-9]+]] ; DBGINFO: for.body3.us: -; DBGINFO-NEXT: #dbg_value(i32 [[B]], [[META89]], !DIExpression(DW_OP_lit0, DW_OP_eq, DW_OP_stack_value), [[META95]]) -; DBGINFO-NEXT: #dbg_value(i8 poison, [[META90:![0-9]+]], !DIExpression(), [[META97:![0-9]+]]) +; DBGINFO-NEXT: [[TOBOOL:%.*]] = icmp eq i32 [[B]], 0, !dbg [[META95]] +; DBGINFO-NEXT: #dbg_value(i1 [[TOBOOL]], [[META89]], !DIExpression(), [[META95]]) +; DBGINFO-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[TOBOOL]], i8 0, i8 4, !dbg [[DBG97:![0-9]+]] +; DBGINFO-NEXT: #dbg_value(i8 [[SPEC_SELECT]], [[META90:![0-9]+]], !DIExpression(), [[DBG97]]) ; DBGINFO-NEXT: switch i3 [[V1:%.*]], label [[EXIT:%.*]] [ ; DBGINFO-NEXT: i3 0, label [[FOR_END:%.*]] ; DBGINFO-NEXT: i3 -1, label [[FOR_END]] @@ -218,9 +224,11 @@ define void @PR36225(i32 %a, i32 %b, i1 %c1, i3 %v1, i3 %v2) { ; DBGINFO-NEXT: i3 -1, label [[FOR_END]] ; DBGINFO-NEXT: ], !dbg [[DBG99:![0-9]+]] ; DBGINFO: for.end: -; DBGINFO-NEXT: #dbg_value(i8 poison, [[META91:![0-9]+]], !DIExpression(), [[META100:![0-9]+]]) -; DBGINFO-NEXT: #dbg_value(i8 0, [[META92:![0-9]+]], !DIExpression(DW_OP_LLVM_convert, 8, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_stack_value), [[META101:![0-9]+]]) -; DBGINFO-NEXT: [[CMP:%.*]] = icmp sgt i32 [[A:%.*]], 0, !dbg [[DBG102:![0-9]+]] +; DBGINFO-NEXT: [[H:%.*]] = phi i8 [ [[SPEC_SELECT]], [[FOR_BODY3_US]] ], [ [[SPEC_SELECT]], [[FOR_BODY3_US]] ], [ 0, [[FOR_BODY3]] ], [ 0, [[FOR_BODY3]] ], !dbg [[DBG100:![0-9]+]] +; DBGINFO-NEXT: #dbg_value(i8 [[H]], [[META91:![0-9]+]], !DIExpression(), [[DBG100]]) +; DBGINFO-NEXT: [[CONV:%.*]] = zext nneg i8 [[H]] to i32, !dbg [[DBG101:![0-9]+]] +; DBGINFO-NEXT: #dbg_value(i32 [[CONV]], [[META92:![0-9]+]], !DIExpression(), [[DBG101]]) +; DBGINFO-NEXT: [[CMP:%.*]] = icmp sgt i32 [[A:%.*]], [[CONV]], !dbg [[DBG102:![0-9]+]] ; DBGINFO-NEXT: #dbg_value(i1 [[CMP]], [[META93:![0-9]+]], !DIExpression(), [[DBG102]]) ; DBGINFO-NEXT: br i1 [[CMP]], label [[EXIT]], label [[EXIT2:%.*]], !dbg [[DBG103:![0-9]+]] ; DBGINFO: exit2: From 5513100d01e9a3db15513cf44868b70913f760c4 Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Sun, 27 Oct 2024 12:59:55 +0800 Subject: [PATCH 8/8] [ValueTracking] Don't infer known bits from select arms --- llvm/lib/Analysis/ValueTracking.cpp | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index 354fbd2e5bc94..73150aad119e4 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -1574,14 +1574,11 @@ static void computeKnownBitsFromOperator(const Operator *I, // If the Use is a select of this phi, use the knownbit of the other // operand to break the recursion. - Value *IncCond = nullptr; - bool InvertIncCond = false; if (auto *SI = dyn_cast(IncValue)) { if (SI->getTrueValue() == P || SI->getFalseValue() == P) { - InvertIncCond = SI->getTrueValue() == P; - IncValue = InvertIncCond ? SI->getFalseValue() : SI->getTrueValue(); + IncValue = SI->getTrueValue() == P ? SI->getFalseValue() + : SI->getTrueValue(); IncDepth = Depth + 1; - IncCond = SI->getCondition(); } } @@ -1594,9 +1591,6 @@ static void computeKnownBitsFromOperator(const Operator *I, Known2 = KnownBits(BitWidth); computeKnownBits(IncValue, DemandedElts, Known2, IncDepth, RecQ); - if (IncCond) - adjustKnownBitsForSelectArm(Known2, IncCond, IncValue, InvertIncCond, - IncDepth, RecQ); // See if we can further use a conditional branch into the phi // to help us determine the range of the value.