[X86] Bump Darwin MaxVectorAlign to 64 when AVX512 is enabled.

Without this, 64-byte vector types (__m512), specified to be 64-byte
aligned in the AVX512 draft SysV ABI, will only be 32-byte aligned.

This is analoguous to AVX, for which we accept 32-byte max alignment.

Differential Revision: http://reviews.llvm.org/D10724

llvm-svn: 246230

1 files changed, 6 insertions, 4 deletions

diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index 503e529bfe2..eee181e7214 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -3640,8 +3640,9 @@ public:
     if (!DarwinTargetInfo<X86_32TargetInfo>::handleTargetFeatures(Features,
                                                                   Diags))
       return false;
-    // Now that we know if we have AVX, we can decide how to align vectors.
-    MaxVectorAlign = hasFeature("avx") ? 256 : 128;
+    // We now know the features we have: we can decide how to align vectors.
+    MaxVectorAlign =
+        hasFeature("avx512f") ? 512 : hasFeature("avx") ? 256 : 128;
     return true;
   }
 };
@@ -4006,8 +4007,9 @@ public:
     if (!DarwinTargetInfo<X86_64TargetInfo>::handleTargetFeatures(Features,
                                                                   Diags))
       return false;
-    // Now that we know if we have AVX, we can decide how to align vectors.
-    MaxVectorAlign = hasFeature("avx") ? 256 : 128;
+    // We now know the features we have: we can decide how to align vectors.
+    MaxVectorAlign =
+        hasFeature("avx512f") ? 512 : hasFeature("avx") ? 256 : 128;
     return true;
   }
 };