[X86][APX] Remove redundant TEST*ri instructions #155586
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
The goal is to remove redundant TEST*ri instructions, especially with NF feature. Other tests are side effects due to longer live range of EFLAGS. https://godbolt.org/z/PbaTj1oa3
Member
|
@llvm/pr-subscribers-backend-x86 Author: Phoebe Wang (phoebewang) ChangesThe goal is to remove redundant TEST*ri instructions, especially with NF feature. Other tests are side effects due to longer live range of EFLAGS. https://godbolt.org/z/PbaTj1oa3 Full diff: https://github.com/llvm/llvm-project/pull/155586.diff 6 Files Affected:
diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
index abf365eedec39..961ff22a2b10f 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -4841,6 +4841,10 @@ bool X86InstrInfo::analyzeCompare(const MachineInstr &MI, Register &SrcReg,
case X86::CMP32ri:
case X86::CMP16ri:
case X86::CMP8ri:
+ case X86::TEST64ri32:
+ case X86::TEST32ri:
+ case X86::TEST16ri:
+ case X86::TEST8ri:
SrcReg = MI.getOperand(0).getReg();
SrcReg2 = 0;
if (MI.getOperand(1).isImm()) {
@@ -4942,6 +4946,10 @@ bool X86InstrInfo::isRedundantFlagInstr(const MachineInstr &FlagI,
case X86::CMP32ri:
case X86::CMP16ri:
case X86::CMP8ri:
+ case X86::TEST64ri32:
+ case X86::TEST32ri:
+ case X86::TEST16ri:
+ case X86::TEST8ri:
CASE_ND(SUB64ri32)
CASE_ND(SUB32ri)
CASE_ND(SUB16ri)
diff --git a/llvm/test/CodeGen/X86/2007-11-30-LoadFolding-Bug.ll b/llvm/test/CodeGen/X86/2007-11-30-LoadFolding-Bug.ll
index 8d690ba06e3bd..6541693776099 100644
--- a/llvm/test/CodeGen/X86/2007-11-30-LoadFolding-Bug.ll
+++ b/llvm/test/CodeGen/X86/2007-11-30-LoadFolding-Bug.ll
@@ -13,25 +13,24 @@ define fastcc void @mp_sqrt(i32 %n, i32 %radix, ptr %in, ptr %out, ptr %tmp1, pt
; CHECK-NEXT: pushl %edi
; CHECK-NEXT: pushl %esi
; CHECK-NEXT: pushl %eax
-; CHECK-NEXT: movb $1, %cl
+; CHECK-NEXT: movb $1, %al
; CHECK-NEXT: movl $1, %ebx
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %esi
; CHECK-NEXT: .p2align 4
; CHECK-NEXT: .LBB0_1: # %bb.i5
; CHECK-NEXT: # =>This Inner Loop Header: Depth=1
-; CHECK-NEXT: movl %ecx, %eax
+; CHECK-NEXT: movl %eax, %ecx
; CHECK-NEXT: addl %ebx, %ebx
-; CHECK-NEXT: xorl %ecx, %ecx
-; CHECK-NEXT: testb $1, %al
+; CHECK-NEXT: xorl %eax, %eax
+; CHECK-NEXT: testb $1, %cl
; CHECK-NEXT: jne .LBB0_1
; CHECK-NEXT: # %bb.2: # %mp_unexp_mp2d.exit.i
; CHECK-NEXT: je .LBB0_3
; CHECK-NEXT: # %bb.5: # %cond_next.i
-; CHECK-NEXT: testb $1, %al
; CHECK-NEXT: jne .LBB0_3
; CHECK-NEXT: # %bb.6: # %cond_next36.i
; CHECK-NEXT: movl $0, 0
-; CHECK-NEXT: movzbl %al, %ebp
+; CHECK-NEXT: movzbl %cl, %ebp
; CHECK-NEXT: andl $1, %ebp
; CHECK-NEXT: xorpd %xmm0, %xmm0
; CHECK-NEXT: xorl %eax, %eax
diff --git a/llvm/test/CodeGen/X86/2008-04-17-CoalescerBug.ll b/llvm/test/CodeGen/X86/2008-04-17-CoalescerBug.ll
index bf939c4131080..3913e93b83a66 100644
--- a/llvm/test/CodeGen/X86/2008-04-17-CoalescerBug.ll
+++ b/llvm/test/CodeGen/X86/2008-04-17-CoalescerBug.ll
@@ -38,7 +38,6 @@ define void @_ZNK10wxDateTime6FormatEPKwRKNS_8TimeZoneE(ptr noalias sret(%struct
; CHECK-NEXT: ## %bb.1: ## %bb116.i
; CHECK-NEXT: je LBB0_25
; CHECK-NEXT: ## %bb.2: ## %bb52.i.i
-; CHECK-NEXT: testb $1, %bl
; CHECK-NEXT: je LBB0_25
; CHECK-NEXT: ## %bb.3: ## %bb142.i
; CHECK-NEXT: je LBB0_25
@@ -49,23 +48,23 @@ define void @_ZNK10wxDateTime6FormatEPKwRKNS_8TimeZoneE(ptr noalias sret(%struct
; CHECK-NEXT: jmp LBB0_5
; CHECK-NEXT: LBB0_21: ## %bb7806
; CHECK-NEXT: ## in Loop: Header=BB0_5 Depth=1
-; CHECK-NEXT: Ltmp16:
+; CHECK-NEXT: Ltmp16: ## EH_LABEL
; CHECK-NEXT: movl $0, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl $1, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl $0, (%esp)
; CHECK-NEXT: calll __ZN12wxStringBase6appendEmw
-; CHECK-NEXT: Ltmp17:
+; CHECK-NEXT: Ltmp17: ## EH_LABEL
; CHECK-NEXT: LBB0_5: ## %bb3261
; CHECK-NEXT: ## =>This Inner Loop Header: Depth=1
; CHECK-NEXT: cmpl $37, 0
; CHECK-NEXT: jne LBB0_25
; CHECK-NEXT: ## %bb.6: ## %bb3306
; CHECK-NEXT: ## in Loop: Header=BB0_5 Depth=1
-; CHECK-NEXT: Ltmp0:
+; CHECK-NEXT: Ltmp0: ## EH_LABEL
; CHECK-NEXT: movl %edi, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl $0, (%esp)
; CHECK-NEXT: calll __ZN12wxStringBaseaSEPKw
-; CHECK-NEXT: Ltmp1:
+; CHECK-NEXT: Ltmp1: ## EH_LABEL
; CHECK-NEXT: ## %bb.7: ## %bb3314
; CHECK-NEXT: ## in Loop: Header=BB0_5 Depth=1
; CHECK-NEXT: movl 0, %eax
@@ -89,11 +88,11 @@ define void @_ZNK10wxDateTime6FormatEPKwRKNS_8TimeZoneE(ptr noalias sret(%struct
; CHECK-NEXT: je LBB0_14
; CHECK-NEXT: ## %bb.13: ## %bb155.i8541
; CHECK-NEXT: ## in Loop: Header=BB0_5 Depth=1
-; CHECK-NEXT: Ltmp4:
+; CHECK-NEXT: Ltmp4: ## EH_LABEL
; CHECK-NEXT: movl $0, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl $0, (%esp)
; CHECK-NEXT: calll _gmtime_r
-; CHECK-NEXT: Ltmp5:
+; CHECK-NEXT: Ltmp5: ## EH_LABEL
; CHECK-NEXT: LBB0_14: ## %bb182.i8560
; CHECK-NEXT: ## in Loop: Header=BB0_5 Depth=1
; CHECK-NEXT: testb $1, %bl
@@ -103,7 +102,7 @@ define void @_ZNK10wxDateTime6FormatEPKwRKNS_8TimeZoneE(ptr noalias sret(%struct
; CHECK-NEXT: je LBB0_18
; CHECK-NEXT: ## %bb.17: ## %bb440.i8663
; CHECK-NEXT: ## in Loop: Header=BB0_5 Depth=1
-; CHECK-NEXT: Ltmp6:
+; CHECK-NEXT: Ltmp6: ## EH_LABEL
; CHECK-NEXT: movl L_.str4$non_lazy_ptr, %eax
; CHECK-NEXT: movl %eax, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl L_.str33$non_lazy_ptr, %eax
@@ -113,47 +112,47 @@ define void @_ZNK10wxDateTime6FormatEPKwRKNS_8TimeZoneE(ptr noalias sret(%struct
; CHECK-NEXT: movl %ebp, (%esp)
; CHECK-NEXT: movl $1717, {{[0-9]+}}(%esp) ## imm = 0x6B5
; CHECK-NEXT: calll __Z10wxOnAssertPKwiPKcS0_S0_
-; CHECK-NEXT: Ltmp7:
+; CHECK-NEXT: Ltmp7: ## EH_LABEL
; CHECK-NEXT: jmp LBB0_18
; CHECK-NEXT: LBB0_15: ## %bb187.i8591
; CHECK-NEXT: ## in Loop: Header=BB0_5 Depth=1
; CHECK-NEXT: jne LBB0_25
; CHECK-NEXT: LBB0_18: ## %invcont5814
; CHECK-NEXT: ## in Loop: Header=BB0_5 Depth=1
-; CHECK-NEXT: Ltmp8:
+; CHECK-NEXT: Ltmp8: ## EH_LABEL
; CHECK-NEXT: movl $0, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl $0, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl $0, (%esp)
; CHECK-NEXT: calll __ZN8wxString6FormatEPKwz
; CHECK-NEXT: subl $4, %esp
-; CHECK-NEXT: Ltmp9:
+; CHECK-NEXT: Ltmp9: ## EH_LABEL
; CHECK-NEXT: ## %bb.19: ## %invcont5831
; CHECK-NEXT: ## in Loop: Header=BB0_5 Depth=1
-; CHECK-NEXT: Ltmp10:
+; CHECK-NEXT: Ltmp10: ## EH_LABEL
; CHECK-NEXT: movl $0, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl $0, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl $0, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl $0, (%esp)
; CHECK-NEXT: calll __ZN12wxStringBase10ConcatSelfEmPKwm
-; CHECK-NEXT: Ltmp11:
+; CHECK-NEXT: Ltmp11: ## EH_LABEL
; CHECK-NEXT: jmp LBB0_5
; CHECK-NEXT: LBB0_9: ## %bb5657
-; CHECK-NEXT: Ltmp13:
+; CHECK-NEXT: Ltmp13: ## EH_LABEL
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: movl %eax, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: movl %eax, (%esp)
; CHECK-NEXT: calll __ZNK10wxDateTime12GetDayOfYearERKNS_8TimeZoneE
-; CHECK-NEXT: Ltmp14:
+; CHECK-NEXT: Ltmp14: ## EH_LABEL
; CHECK-NEXT: jmp LBB0_25
; CHECK-NEXT: LBB0_20: ## %bb5968
-; CHECK-NEXT: Ltmp2:
+; CHECK-NEXT: Ltmp2: ## EH_LABEL
; CHECK-NEXT: movl $0, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl $0, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl $0, (%esp)
; CHECK-NEXT: calll __ZN8wxString6FormatEPKwz
; CHECK-NEXT: subl $4, %esp
-; CHECK-NEXT: Ltmp3:
+; CHECK-NEXT: Ltmp3: ## EH_LABEL
; CHECK-NEXT: LBB0_25: ## %bb115.critedge.i
; CHECK-NEXT: movl %esi, %eax
; CHECK-NEXT: addl $28, %esp
@@ -163,13 +162,13 @@ define void @_ZNK10wxDateTime6FormatEPKwRKNS_8TimeZoneE(ptr noalias sret(%struct
; CHECK-NEXT: popl %ebp
; CHECK-NEXT: retl $4
; CHECK-NEXT: LBB0_23: ## %lpad.loopexit.split-lp
-; CHECK-NEXT: Ltmp15:
+; CHECK-NEXT: Ltmp15: ## EH_LABEL
; CHECK-NEXT: jmp LBB0_25
; CHECK-NEXT: LBB0_24: ## %lpad8185
-; CHECK-NEXT: Ltmp12:
+; CHECK-NEXT: Ltmp12: ## EH_LABEL
; CHECK-NEXT: jmp LBB0_25
; CHECK-NEXT: LBB0_22: ## %lpad.loopexit
-; CHECK-NEXT: Ltmp18:
+; CHECK-NEXT: Ltmp18: ## EH_LABEL
; CHECK-NEXT: jmp LBB0_25
; CHECK-NEXT: Lfunc_end0:
entry:
diff --git a/llvm/test/CodeGen/X86/apx/cf.ll b/llvm/test/CodeGen/X86/apx/cf.ll
index e52ce6ca815bb..b2651e91134ee 100644
--- a/llvm/test/CodeGen/X86/apx/cf.ll
+++ b/llvm/test/CodeGen/X86/apx/cf.ll
@@ -229,3 +229,21 @@ entry:
call void @llvm.masked.store.v1i32.p0(<1 x i32> zeroinitializer, ptr %p, i32 1, <1 x i1> %1)
ret void
}
+
+define i64 @redundant_test(i64 %num, ptr %p1, i64 %in) {
+; CHECK-LABEL: redundant_test:
+; CHECK: # %bb.0:
+; CHECK-NEXT: testl $-32, %edi
+; CHECK-NEXT: cfcmoveq (%rsi), %rax
+; CHECK-NEXT: {nf} addq %rdx, %rax
+; CHECK-NEXT: cmovneq %rdi, %rax
+; CHECK-NEXT: retq
+ %and = and i64 %num, 4294967264
+ %cmp = icmp eq i64 %and, 0
+ %mask = bitcast i1 %cmp to <1 x i1>
+ %condload = tail call <1 x i64> @llvm.masked.load.v1i64.p0(ptr %p1, i32 8, <1 x i1> %mask, <1 x i64> poison)
+ %v = bitcast <1 x i64> %condload to i64
+ %add = add i64 %v, %in
+ %sel = select i1 %cmp, i64 %add, i64 %num
+ ret i64 %sel
+}
diff --git a/llvm/test/CodeGen/X86/ins_subreg_coalesce-3.ll b/llvm/test/CodeGen/X86/ins_subreg_coalesce-3.ll
index 3ac0fd7746a30..eccb32346a403 100644
--- a/llvm/test/CodeGen/X86/ins_subreg_coalesce-3.ll
+++ b/llvm/test/CodeGen/X86/ins_subreg_coalesce-3.ll
@@ -22,41 +22,45 @@ define void @FontChange(i1 %foo) nounwind {
; CHECK-LABEL: FontChange:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: testb $1, %dil
-; CHECK-NEXT: je .LBB0_10
+; CHECK-NEXT: je .LBB0_12
+; CHECK-NEXT: # %bb.1: # %bb298
+; CHECK-NEXT: je .LBB0_3
+; CHECK-NEXT: # %bb.2: # %bb304
+; CHECK-NEXT: je .LBB0_4
; CHECK-NEXT: .p2align 4
-; CHECK-NEXT: .LBB0_1: # %bb366
+; CHECK-NEXT: .LBB0_3: # %bb366
; CHECK-NEXT: # =>This Inner Loop Header: Depth=1
; CHECK-NEXT: testb $1, %dil
-; CHECK-NEXT: jne .LBB0_1
-; CHECK-NEXT: # %bb.2: # %bb428
+; CHECK-NEXT: jne .LBB0_3
+; CHECK-NEXT: .LBB0_4: # %bb428
; CHECK-NEXT: testb $1, %dil
-; CHECK-NEXT: je .LBB0_10
-; CHECK-NEXT: # %bb.3:
+; CHECK-NEXT: je .LBB0_12
+; CHECK-NEXT: # %bb.5:
; CHECK-NEXT: cmpb $0, 0
; CHECK-NEXT: .p2align 4
-; CHECK-NEXT: .LBB0_4: # %bb650
+; CHECK-NEXT: .LBB0_6: # %bb650
; CHECK-NEXT: # =>This Inner Loop Header: Depth=1
-; CHECK-NEXT: je .LBB0_4
-; CHECK-NEXT: # %bb.5: # %bb662
+; CHECK-NEXT: je .LBB0_6
+; CHECK-NEXT: # %bb.7: # %bb662
; CHECK-NEXT: movl 0, %eax
; CHECK-NEXT: movl %eax, %ecx
; CHECK-NEXT: andl $57344, %ecx # imm = 0xE000
; CHECK-NEXT: cmpl $8192, %ecx # imm = 0x2000
-; CHECK-NEXT: jne .LBB0_10
-; CHECK-NEXT: # %bb.6: # %bb4884
+; CHECK-NEXT: jne .LBB0_12
+; CHECK-NEXT: # %bb.8: # %bb4884
; CHECK-NEXT: andl $7168, %eax # imm = 0x1C00
; CHECK-NEXT: cmpl $1024, %eax # imm = 0x400
-; CHECK-NEXT: jne .LBB0_10
-; CHECK-NEXT: # %bb.7: # %bb4932
+; CHECK-NEXT: jne .LBB0_12
+; CHECK-NEXT: # %bb.9: # %bb4932
; CHECK-NEXT: testb $1, %dil
-; CHECK-NEXT: jne .LBB0_10
-; CHECK-NEXT: # %bb.8: # %bb4940
+; CHECK-NEXT: jne .LBB0_12
+; CHECK-NEXT: # %bb.10: # %bb4940
; CHECK-NEXT: movl 0, %eax
; CHECK-NEXT: cmpl $160, %eax
-; CHECK-NEXT: je .LBB0_10
-; CHECK-NEXT: # %bb.9: # %bb4940
+; CHECK-NEXT: je .LBB0_12
+; CHECK-NEXT: # %bb.11: # %bb4940
; CHECK-NEXT: cmpl $159, %eax
-; CHECK-NEXT: .LBB0_10: # %bb4897
+; CHECK-NEXT: .LBB0_12: # %bb4897
; CHECK-NEXT: retq
entry:
br i1 %foo, label %bb298, label %bb49
diff --git a/llvm/test/CodeGen/X86/pr38795.ll b/llvm/test/CodeGen/X86/pr38795.ll
index c3c96e8228797..6a0c13526ac18 100644
--- a/llvm/test/CodeGen/X86/pr38795.ll
+++ b/llvm/test/CodeGen/X86/pr38795.ll
@@ -260,7 +260,6 @@ define void @verifier_error_reduced_issue38788(i1 %cmp11) {
; CHECK-NEXT: pushl %ebx
; CHECK-NEXT: .cfi_def_cfa_offset 8
; CHECK-NEXT: .cfi_offset %ebx, -8
-; CHECK-NEXT: movzbl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: xorl %ecx, %ecx
; CHECK-NEXT: xorl %ebx, %ebx
; CHECK-NEXT: jmp .LBB1_1
@@ -272,10 +271,9 @@ define void @verifier_error_reduced_issue38788(i1 %cmp11) {
; CHECK-NEXT: # in Loop: Header=BB1_1 Depth=1
; CHECK-NEXT: movl %eax, %ecx
; CHECK-NEXT: movl %edx, %ebx
-; CHECK-NEXT: movzbl {{[0-9]+}}(%esp), %eax
; CHECK-NEXT: .LBB1_1: # %for.cond
; CHECK-NEXT: # =>This Inner Loop Header: Depth=1
-; CHECK-NEXT: testb $1, %al
+; CHECK-NEXT: testb $1, {{[0-9]+}}(%esp)
; CHECK-NEXT: je .LBB1_3
; CHECK-NEXT: # %bb.2: # in Loop: Header=BB1_1 Depth=1
; CHECK-NEXT: xorl %eax, %eax
@@ -283,12 +281,11 @@ define void @verifier_error_reduced_issue38788(i1 %cmp11) {
; CHECK-NEXT: .p2align 4
; CHECK-NEXT: .LBB1_3: # %if.end
; CHECK-NEXT: # in Loop: Header=BB1_1 Depth=1
-; CHECK-NEXT: testb $1, %al
; CHECK-NEXT: je .LBB1_4
; CHECK-NEXT: # %bb.9: # %if.then13
; CHECK-NEXT: # in Loop: Header=BB1_1 Depth=1
; CHECK-NEXT: xorl %edx, %edx
-; CHECK-NEXT: testb $1, %al
+; CHECK-NEXT: testb $1, {{[0-9]+}}(%esp)
; CHECK-NEXT: movl %ebx, %eax
; CHECK-NEXT: movl $0, %ebx
; CHECK-NEXT: jne .LBB1_8
|
You can test this locally with the following command:git-clang-format --diff HEAD~1 HEAD --extensions cpp -- llvm/lib/Target/X86/X86InstrInfo.cppView the diff from clang-format here.diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
index 76c92f4ff..6e7bf804a 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -4945,10 +4945,10 @@ bool X86InstrInfo::isRedundantFlagInstr(const MachineInstr &FlagI,
case X86::TEST32ri:
case X86::TEST16ri:
case X86::TEST8ri:
- CASE_ND(SUB64ri32)
- CASE_ND(SUB32ri)
- CASE_ND(SUB16ri)
- CASE_ND(SUB8ri)
+ CASE_ND(SUB64ri32)
+ CASE_ND(SUB32ri)
+ CASE_ND(SUB16ri)
+ CASE_ND(SUB8ri)
case X86::TEST64rr:
case X86::TEST32rr:
case X86::TEST16rr:
|
KanRobert
approved these changes
Aug 27, 2025
RKSimon
reviewed
Aug 27, 2025
| ; CHECK-NEXT: # %bb.1: # %bb298 | ||
| ; CHECK-NEXT: je .LBB0_3 | ||
| ; CHECK-NEXT: # %bb.2: # %bb304 | ||
| ; CHECK-NEXT: je .LBB0_4 |
Contributor
There was a problem hiding this comment.
Ah, I didn't notice this.
Contributor
Author
There was a problem hiding this comment.
It is a side effect due to longer live range of EFLAGS. MIR before Control Flow Optimizer:
MIR after Control Flow Optimizer:
LHS is generated with this patch.
I think it's not specific to TEST*ri instructions. And the IR is verbose in branching the same condition. It should not occur in real workload: https://godbolt.org/z/nrKajM3Mc
Collaborator
There was a problem hiding this comment.
ok - that makes sense - cheers
RKSimon
approved these changes
Aug 27, 2025
Contributor
|
We are seeing a build failure on our stage2 builders after this patch landed. We conducted a bisecting and confirmed that this patch caused the issue. It looks like this patch caused a miscompile and in the stage2 build, the tablegen generated header no longer satisfied the UTF-8 format and triggering parsing error from the clang. See the detailed error message: Failed build task: https://ci.chromium.org/ui/p/fuchsia/builders/prod/clang-linux-x64/b8705318044182027361/overview |
Member
|
I also bisected strange behavior to this change, namely an |
vitalybuka
added a commit
that referenced
this pull request
Aug 29, 2025
This reverts commit 9c9e56b.
vitalybuka
added a commit
that referenced
this pull request
Aug 29, 2025
llvm-sync bot
pushed a commit
to arm/arm-toolchain
that referenced
this pull request
Aug 29, 2025
…(#155968) Reverts llvm/llvm-project#155586 Breaks bots, see details in #155586.
Member
|
I also ran into this issue. The miscompilations can be reproduced with https://martin.st/temp/apv_entropy-preproc.c, compiled with --- good.s 2025-08-29 09:34:24.970634708 +0300
+++ bad.s 2025-08-29 09:34:16.822610156 +0300
@@ -1228,7 +1228,6 @@
jmp .LBB1_19
.LBB1_34: # %if.else157
movl %r11d, %r9d
- testb $1, %cl
jne .LBB1_69
jmp .LBB1_55
.LBB1_35: # %if.end104It's possible to reproduce the failures at runtime, by cloning http://github.com/ffmpeg/ffmpeg, configuring it with |
Contributor
Author
|
Thanks all! I have root caused the problem. Created #156002 for reland. |
Contributor
Author
Great! It's very helpful! |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
8 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The goal is to remove redundant TEST*ri instructions, especially with NF feature. Other tests are side effects due to longer live range of EFLAGS. https://godbolt.org/z/PbaTj1oa3