[ms-inline-asm] Use the frontend size only for ambiguous instructions

This avoids problems on code like this:
  char buf[16];
  __asm {
    movups xmm0, [buf]
    mov [buf], eax
  }

The frontend size in this case (1) is wrong, and the register makes the
instruction matching unambiguous. There are also enough bytes available
that we shouldn't complain to the user that they are potentially using
an incorrectly sized instruction to access the variable.

Supersedes D32636 and D26586 and fixes PR28266

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@302179 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 1 deletions

diff --git a/test/CodeGen/ms-inline-asm-avx512.c b/test/CodeGen/ms-inline-asm-avx512.c
index c1b783a210..6189e50d21 100644
--- a/test/CodeGen/ms-inline-asm-avx512.c
+++ b/test/CodeGen/ms-inline-asm-avx512.c
@@ -1,5 +1,5 @@
 // REQUIRES: x86-registered-target
-// RUN: %clang_cc1 %s -triple x86_64-pc-windows-msvc -target-cpu knl -fasm-blocks -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 %s -triple x86_64-pc-windows-msvc -target-cpu skylake-avx512 -fasm-blocks -emit-llvm -o - | FileCheck %s
 
 void t1() {
 // CHECK: @t1
@@ -19,3 +19,16 @@ void t2() {
 	  vaddpd zmm8 {k1}, zmm27, zmm6
   }
 }
+
+void ignore_fe_size() {
+  // CHECK-LABEL: define void @ignore_fe_size()
+  char c;
+  // CHECK: vaddps xmm1, xmm2, $1{1to4}
+  __asm vaddps xmm1, xmm2, [c]{1to4}
+  // CHECK: vaddps xmm1, xmm2, $2
+  __asm vaddps xmm1, xmm2, [c]
+  // CHECK: mov eax, $3
+  __asm mov eax, [c]
+  // CHECK: mov $0, rax
+  __asm mov [c], rax
+}