[llvm-bugs] [Bug 34021] New: MS Inline assembly with vector type causes a bad trunc emission.

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=34021

            Bug ID: 34021
           Summary: MS Inline assembly with vector type causes a bad trunc
                    emission.
           Product: clang
           Version: trunk
          Hardware: PC
                OS: Windows NT
            Status: NEW
          Severity: normal
          Priority: P
         Component: LLVM Codegen
          Assignee: unassignedclangbugs at nondot.org
          Reporter: erich.keane at intel.com
                CC: llvm-bugs at lists.llvm.org, rnk at google.com

Code: 
typedef int v4si __attribute__ ((vector_size (16)));
v4si rep() {
    v4si res;
    __asm {}
    return res;
}

Compile with: -O0 -fms-extensions -m32
Result is a crash in DAG due to a trunc that widens instead of narrows.  
Higher optimizer levels cause this to disappear, presumably due to instcombine.

Our original repro:
 #include <emmintrin.h>
 __m128i x;

 __m128i foo ()
 {
      __asm {
          movdqu xmm0, xmm1
      }
     return x;
 }


Also should validate that the following works:
#include <emmintrin.h>
 __m128i x;

 __m128i foo ()
 {
      __asm {
          movdqu xmm0, x
      }
 }

int main () {
    foo();
    return 0;
 }

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20170801/56138554/attachment.html>