[clang] d298acd - [X86] Don't disable xsave when avx is disabled. Implicitly enable xsave with avx is enabled and xsave wasn't explciitly disabled

[Craig Topper via cfe-commits]

Author: Craig Topper
Date: 2020-06-26T16:45:44-07:00
New Revision: d298acde828f4abc5e7c82ba1f6092890d910097

URL: https://github.com/llvm/llvm-project/commit/d298acde828f4abc5e7c82ba1f6092890d910097
DIFF: https://github.com/llvm/llvm-project/commit/d298acde828f4abc5e7c82ba1f6092890d910097.diff

LOG: [X86] Don't disable xsave when avx is disabled. Implicitly enable xsave with avx is enabled and xsave wasn't explciitly disabled

CPUs with avx always have xsave, but some CPUs without avx also
have xsave. So we shouldn't disable xsave just because avx is
disabled. This would prevent xsave from being enabled with
-march=native on CPUs with xsave and not avx.

But we also don't want -mavx -mno-avx to leave xsave eanabled.
So only enable xsave if avx is enabled after processing all features.

I thought about just not turning xsave on with avx at all, but
there might be someone out there depending on it.

Added: 
    

Modified: 
    clang/lib/Basic/Targets/X86.cpp
    clang/test/CodeGen/attr-target-x86.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/Basic/Targets/X86.cpp b/clang/lib/Basic/Targets/X86.cpp
index 22ed922e678e..fdc59f0583ba 100644
--- a/clang/lib/Basic/Targets/X86.cpp
+++ b/clang/lib/Basic/Targets/X86.cpp
@@ -360,6 +360,7 @@ bool X86TargetInfo::initFeatureMap(
     setFeatureEnabledImpl(Features, "bmi", true);
     setFeatureEnabledImpl(Features, "f16c", true);
     setFeatureEnabledImpl(Features, "xsaveopt", true);
+    setFeatureEnabledImpl(Features, "xsave", true);
     setFeatureEnabledImpl(Features, "movbe", true);
     LLVM_FALLTHROUGH;
   case CK_BTVER1:
@@ -459,6 +460,12 @@ bool X86TargetInfo::initFeatureMap(
       llvm::find(FeaturesVec, "-mmx") == FeaturesVec.end())
     Features["mmx"] = true;
 
+  // Enable xsave if avx is enabled and xsave is not explicitly disabled.
+  I = Features.find("avx");
+  if (I != Features.end() && I->getValue() &&
+      llvm::find(FeaturesVec, "-xsave") == FeaturesVec.end())
+    Features["xsave"] = true;
+
   return true;
 }
 
@@ -476,7 +483,6 @@ void X86TargetInfo::setSSELevel(llvm::StringMap<bool> &Features,
       LLVM_FALLTHROUGH;
     case AVX:
       Features["avx"] = true;
-      Features["xsave"] = true;
       LLVM_FALLTHROUGH;
     case SSE42:
       Features["sse4.2"] = true;
@@ -526,8 +532,7 @@ void X86TargetInfo::setSSELevel(llvm::StringMap<bool> &Features,
     LLVM_FALLTHROUGH;
   case AVX:
     Features["fma"] = Features["avx"] = Features["f16c"] = false;
-    Features["xsave"] = Features["xsaveopt"] = Features["vaes"] = false;
-    Features["vpclmulqdq"] = false;
+    Features["vaes"] = Features["vpclmulqdq"] = false;
     setXOPLevel(Features, FMA4, false);
     LLVM_FALLTHROUGH;
   case AVX2:

diff  --git a/clang/test/CodeGen/attr-target-x86.c b/clang/test/CodeGen/attr-target-x86.c
index 73486e5ee1fe..feed175cce0b 100644
--- a/clang/test/CodeGen/attr-target-x86.c
+++ b/clang/test/CodeGen/attr-target-x86.c
@@ -50,9 +50,9 @@ int __attribute__((target("arch=lakemont,mmx"))) use_before_def(void) {
 // CHECK: use_before_def{{.*}} #7
 // CHECK: #0 = {{.*}}"target-cpu"="i686" "target-features"="+cx8,+x87"
 // CHECK: #1 = {{.*}}"target-cpu"="ivybridge" "target-features"="+avx,+cx16,+cx8,+f16c,+fsgsbase,+fxsr,+mmx,+pclmul,+popcnt,+rdrnd,+sahf,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+ssse3,+x87,+xsave,+xsaveopt"
-// CHECK: #2 = {{.*}}"target-cpu"="i686" "target-features"="+cx8,+x87,-aes,-avx,-avx2,-avx512bf16,-avx512bitalg,-avx512bw,-avx512cd,-avx512dq,-avx512er,-avx512f,-avx512ifma,-avx512pf,-avx512vbmi,-avx512vbmi2,-avx512vl,-avx512vnni,-avx512vp2intersect,-avx512vpopcntdq,-f16c,-fma,-fma4,-gfni,-pclmul,-sha,-sse2,-sse3,-sse4.1,-sse4.2,-sse4a,-ssse3,-vaes,-vpclmulqdq,-xop,-xsave,-xsaveopt"
+// CHECK: #2 = {{.*}}"target-cpu"="i686" "target-features"="+cx8,+x87,-aes,-avx,-avx2,-avx512bf16,-avx512bitalg,-avx512bw,-avx512cd,-avx512dq,-avx512er,-avx512f,-avx512ifma,-avx512pf,-avx512vbmi,-avx512vbmi2,-avx512vl,-avx512vnni,-avx512vp2intersect,-avx512vpopcntdq,-f16c,-fma,-fma4,-gfni,-pclmul,-sha,-sse2,-sse3,-sse4.1,-sse4.2,-sse4a,-ssse3,-vaes,-vpclmulqdq,-xop"
 // CHECK: #3 = {{.*}}"target-cpu"="i686" "target-features"="+cx8,+mmx,+popcnt,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+ssse3,+x87"
-// CHECK: #4 = {{.*}}"target-cpu"="i686" "target-features"="+cx8,+x87,-avx,-avx2,-avx512bf16,-avx512bitalg,-avx512bw,-avx512cd,-avx512dq,-avx512er,-avx512f,-avx512ifma,-avx512pf,-avx512vbmi,-avx512vbmi2,-avx512vl,-avx512vnni,-avx512vp2intersect,-avx512vpopcntdq,-f16c,-fma,-fma4,-sse4.1,-sse4.2,-vaes,-vpclmulqdq,-xop,-xsave,-xsaveopt"
+// CHECK: #4 = {{.*}}"target-cpu"="i686" "target-features"="+cx8,+x87,-avx,-avx2,-avx512bf16,-avx512bitalg,-avx512bw,-avx512cd,-avx512dq,-avx512er,-avx512f,-avx512ifma,-avx512pf,-avx512vbmi,-avx512vbmi2,-avx512vl,-avx512vnni,-avx512vp2intersect,-avx512vpopcntdq,-f16c,-fma,-fma4,-sse4.1,-sse4.2,-vaes,-vpclmulqdq,-xop"
 // CHECK: #5 = {{.*}}"target-cpu"="ivybridge" "target-features"="+avx,+cx16,+cx8,+f16c,+fsgsbase,+fxsr,+mmx,+pclmul,+popcnt,+rdrnd,+sahf,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+ssse3,+x87,+xsave,+xsaveopt,-aes,-vaes"
 // CHECK: #6 = {{.*}}"target-cpu"="i686" "target-features"="+cx8,+x87,-3dnow,-3dnowa,-mmx"
 // CHECK: #7 = {{.*}}"target-cpu"="lakemont" "target-features"="+cx8,+mmx"