Remove 3DNow! from X86TargetParser. (#99352)

This addresses the spurious inclusion of (now unsupported) target
features '-3dnow' and '-3dnowa' when disabling mmx (when then caused log
output from `clang -mno-mmx`).

It should've been part of PR #96246, but was missed.

Also tweaks the warning in prfchwintrin.h to not recommend the
deprecated mm3dnow.h header.

Author: jyknight

clang/lib/Headers/prfchwintrin.h

@@ -8,7 +8,7 @@
  */
 
 #if !defined(__X86INTRIN_H) && !defined(_MM3DNOW_H_INCLUDED)
-#error "Never use <prfchwintrin.h> directly; include <x86intrin.h> or <mm3dnow.h> instead."
+#error "Never use <prfchwintrin.h> directly; include <x86intrin.h> instead."
 #endif
 
 #ifndef __PRFCHWINTRIN_H

clang/test/CodeGen/attr-target-x86.c

@@ -64,7 +64,7 @@ void __attribute__((target("avx10.1-512"))) avx10_1_512(void) {}
 // CHECK: #4 = {{.*}}"target-cpu"="i686" "target-features"="+cmov,+cx8,+x87,-avx,-avx10.1-256,-avx10.1-512,-avx2,-avx512bf16,-avx512bitalg,-avx512bw,-avx512cd,-avx512dq,-avx512f,-avx512fp16,-avx512ifma,-avx512vbmi,-avx512vbmi2,-avx512vl,-avx512vnni,-avx512vp2intersect,-avx512vpopcntdq,-avxifma,-avxneconvert,-avxvnni,-avxvnniint16,-avxvnniint8,-f16c,-fma,-fma4,-sha512,-sm3,-sm4,-sse4.1,-sse4.2,-vaes,-vpclmulqdq,-xop" "tune-cpu"="i686"
 // CHECK: #5 = {{.*}}"target-cpu"="ivybridge" "target-features"="+avx,+cmov,+crc32,+cx16,+cx8,+f16c,+fsgsbase,+fxsr,+mmx,+pclmul,+popcnt,+rdrnd,+sahf,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+ssse3,+x87,+xsave,+xsaveopt,-aes,-avx10.1-256,-avx10.1-512,-vaes"
 // CHECK-NOT: tune-cpu
-// CHECK: #6 = {{.*}}"target-cpu"="i686" "target-features"="+cmov,+cx8,+x87,-3dnow,-3dnowa,-mmx"
+// CHECK: #6 = {{.*}}"target-cpu"="i686" "target-features"="+cmov,+cx8,+x87,-mmx"
 // CHECK: #7 = {{.*}}"target-cpu"="lakemont" "target-features"="+cx8,+mmx"
 // CHECK-NOT: tune-cpu
 // CHECK: #8 = {{.*}}"target-cpu"="i686" "target-features"="+cmov,+cx8,+x87" "tune-cpu"="sandybridge"

compiler-rt/lib/builtins/cpu_model/x86.c

@@ -141,7 +141,7 @@ enum ProcessorFeatures {
   FEATURE_AVX512VP2INTERSECT,
   // FIXME: Below Features has some missings comparing to gcc, it's because gcc
   // has some not one-to-one mapped in llvm.
-  FEATURE_3DNOW,
+  // FEATURE_3DNOW,
   // FEATURE_3DNOWP,
   FEATURE_ADX = 40,
   // FEATURE_ABM,

llvm/include/llvm/TargetParser/X86TargetParser.def

@@ -175,8 +175,12 @@ X86_FEATURE_COMPAT(AVX512BF16,      "avx512bf16",            34)
 X86_FEATURE_COMPAT(AVX512VP2INTERSECT, "avx512vp2intersect", 35)
 // Below Features has some missings comparing to gcc, it's because gcc has some
 // not one-to-one mapped in llvm.
-X86_FEATURE_COMPAT(3DNOW,           "3dnow",                  0)
-X86_FEATURE       (3DNOWA,          "3dnowa")
+
+// FIXME: dummy features were added to keep the numeric values of later features
+// stable. Since the values need to be ABI stable, they should be changed to
+// have explicitly assigned values, and then these dummy features removed.
+X86_FEATURE       (DUMMYFEATURE1,   "__dummyfeature1")
+X86_FEATURE       (DUMMYFEATURE2,   "__dummyfeature2")
 X86_FEATURE_COMPAT(ADX,             "adx",                    0)
 X86_FEATURE       (64BIT,           "64bit")
 X86_FEATURE_COMPAT(CLDEMOTE,        "cldemote",               0)

llvm/lib/TargetParser/X86TargetParser.cpp

@@ -171,14 +171,14 @@ constexpr FeatureBitset FeaturesClearwaterforest =
 
 // Geode Processor.
 constexpr FeatureBitset FeaturesGeode =
-    FeatureX87 | FeatureCMPXCHG8B | FeatureMMX | Feature3DNOW | Feature3DNOWA;
+    FeatureX87 | FeatureCMPXCHG8B | FeatureMMX | FeaturePRFCHW;
 
 // K6 processor.
 constexpr FeatureBitset FeaturesK6 = FeatureX87 | FeatureCMPXCHG8B | FeatureMMX;
 
 // K7 and K8 architecture processors.
 constexpr FeatureBitset FeaturesAthlon =
-    FeatureX87 | FeatureCMPXCHG8B | FeatureMMX | Feature3DNOW | Feature3DNOWA;
+    FeatureX87 | FeatureCMPXCHG8B | FeatureMMX | FeaturePRFCHW;
 constexpr FeatureBitset FeaturesAthlonXP =
     FeaturesAthlon | FeatureFXSR | FeatureSSE;
 constexpr FeatureBitset FeaturesK8 =
@@ -256,8 +256,8 @@ constexpr ProcInfo Processors[] = {
   // i486-generation processors.
   { {"i486"}, CK_i486, ~0U, FeatureX87, '\0', false },
   { {"winchip-c6"}, CK_WinChipC6, ~0U, FeaturesPentiumMMX, '\0', false },
-  { {"winchip2"}, CK_WinChip2, ~0U, FeaturesPentiumMMX | Feature3DNOW, '\0', false },
-  { {"c3"}, CK_C3, ~0U, FeaturesPentiumMMX | Feature3DNOW, '\0', false },
+  { {"winchip2"}, CK_WinChip2, ~0U, FeaturesPentiumMMX | FeaturePRFCHW, '\0', false },
+  { {"c3"}, CK_C3, ~0U, FeaturesPentiumMMX | FeaturePRFCHW, '\0', false },
   // i586-generation processors, P5 microarchitecture based.
   { {"i586"}, CK_i586, ~0U, FeatureX87 | FeatureCMPXCHG8B, '\0', false },
   { {"pentium"}, CK_Pentium, ~0U, FeatureX87 | FeatureCMPXCHG8B, 'B', false },
@@ -386,8 +386,8 @@ constexpr ProcInfo Processors[] = {
   { {"lakemont"}, CK_Lakemont, ~0U, FeatureCMPXCHG8B, '\0', false },
   // K6 architecture processors.
   { {"k6"}, CK_K6, ~0U, FeaturesK6, '\0', false },
-  { {"k6-2"}, CK_K6_2, ~0U, FeaturesK6 | Feature3DNOW, '\0', false },
-  { {"k6-3"}, CK_K6_3, ~0U, FeaturesK6 | Feature3DNOW, '\0', false },
+  { {"k6-2"}, CK_K6_2, ~0U, FeaturesK6 | FeaturePRFCHW, '\0', false },
+  { {"k6-3"}, CK_K6_3, ~0U, FeaturesK6 | FeaturePRFCHW, '\0', false },
   // K7 architecture processors.
   { {"athlon"}, CK_Athlon, ~0U, FeaturesAthlon, '\0', false },
   { {"athlon-tbird"}, CK_Athlon, ~0U, FeaturesAthlon, '\0', false },
@@ -493,6 +493,7 @@ constexpr FeatureBitset ImpliedFeaturesFXSR = {};
 constexpr FeatureBitset ImpliedFeaturesINVPCID = {};
 constexpr FeatureBitset ImpliedFeaturesLWP = {};
 constexpr FeatureBitset ImpliedFeaturesLZCNT = {};
+constexpr FeatureBitset ImpliedFeaturesMMX = {};
 constexpr FeatureBitset ImpliedFeaturesMWAITX = {};
 constexpr FeatureBitset ImpliedFeaturesMOVBE = {};
 constexpr FeatureBitset ImpliedFeaturesMOVDIR64B = {};
@@ -520,6 +521,8 @@ constexpr FeatureBitset ImpliedFeaturesWBNOINVD = {};
 constexpr FeatureBitset ImpliedFeaturesVZEROUPPER = {};
 constexpr FeatureBitset ImpliedFeaturesX87 = {};
 constexpr FeatureBitset ImpliedFeaturesXSAVE = {};
+constexpr FeatureBitset ImpliedFeaturesDUMMYFEATURE1 = {};
+constexpr FeatureBitset ImpliedFeaturesDUMMYFEATURE2 = {};
 
 // Not really CPU features, but need to be in the table because clang uses
 // target features to communicate them to the backend.
@@ -534,11 +537,6 @@ constexpr FeatureBitset ImpliedFeaturesXSAVEC = FeatureXSAVE;
 constexpr FeatureBitset ImpliedFeaturesXSAVEOPT = FeatureXSAVE;
 constexpr FeatureBitset ImpliedFeaturesXSAVES = FeatureXSAVE;
 
-// MMX->3DNOW->3DNOWA chain.
-constexpr FeatureBitset ImpliedFeaturesMMX = {};
-constexpr FeatureBitset ImpliedFeatures3DNOW = FeatureMMX;
-constexpr FeatureBitset ImpliedFeatures3DNOWA = Feature3DNOW;
-
 // SSE/AVX/AVX512F chain.
 constexpr FeatureBitset ImpliedFeaturesSSE = {};
 constexpr FeatureBitset ImpliedFeaturesSSE2 = FeatureSSE;