[x86] Fix a really nasty bug introduced in r276417 where alignment

constraints were added to _mm256_broadcast_{pd,ps} intel intrinsics.

The spec for these intrinics is ... pretty much silent on alignment.
This is especially frustrating considering the amount of discussion of
alignment in the load and store instrinsics. So I was forced to rely on
the specification for the VBROADCASTF128 instruction.

That instruction's spec is *also* completely silent on alignment.
Fortunately, when it comes to the instruction's spec, silence is enough.
There is no #GP fault option for an underaligned address so this
instruction, and by inference the intrinsic, can read any alignment.

As it happens, the old code worked exactly this way and in fact we have
plenty of code that hands pointers with less than 16-byte alignment to
these intrinsics. This code broke pretty spectacularly with this commit.

Fortunately, the fix is super simple! Change a 16 to a 1, and ta da!

Anyways, a lot of debugging for a really boring fix. =]

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@278202 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 5f47cb4e3d716480731f03a977ea777125110d03..87a825d46ade7f535b769cab6585e60173fb3332 100644 (file)
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -7020,7 +7020,7 @@ Value *CodeGenFunction::EmitX86BuiltinExpr(unsigned BuiltinID,
   case X86::BI__builtin_ia32_vbroadcastf128_pd256:
   case X86::BI__builtin_ia32_vbroadcastf128_ps256: {
     llvm::Type *DstTy = ConvertType(E->getType());
-    return EmitX86SubVectorBroadcast(*this, Ops, DstTy, 128, 16);
+    return EmitX86SubVectorBroadcast(*this, Ops, DstTy, 128, 1);
   }
 
   case X86::BI__builtin_ia32_storehps:

diff --git a/test/CodeGen/avx-builtins.c b/test/CodeGen/avx-builtins.c
index d7e6a0beb714d1a333c3ab12c2413c6904e77111..8851181f56dd0c932881f7528c65ec1190fc0f1a 100644 (file)
--- a/test/CodeGen/avx-builtins.c
+++ b/test/CodeGen/avx-builtins.c
@@ -84,14 +84,14 @@ __m256 test_mm256_blendv_ps(__m256 V1, __m256 V2, __m256 V3) {
 
 __m256d test_mm256_broadcast_pd(__m128d* A) {
   // CHECK-LABEL: test_mm256_broadcast_pd
-  // CHECK: load <2 x double>, <2 x double>* %{{.*}}, align 16
+  // CHECK: load <2 x double>, <2 x double>* %{{.*}}, align 1
   // CHECK: shufflevector <2 x double> %{{.*}}, <2 x double> %{{.*}}, <4 x i32> <i32 0, i32 1, i32 0, i32 1>
   return _mm256_broadcast_pd(A);
 }
 
 __m256 test_mm256_broadcast_ps(__m128* A) {
   // CHECK-LABEL: test_mm256_broadcast_ps
-  // CHECK: load <4 x float>, <4 x float>* %{{.*}}, align 16
+  // CHECK: load <4 x float>, <4 x float>* %{{.*}}, align 1
   // CHECK: shufflevector <4 x float> %{{.*}}, <4 x float> %{{.*}}, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 0, i32 1, i32 2, i32 3>
   return _mm256_broadcast_ps(A);
 }