[LLVMbugs] [Bug 7567] New: clang generates movaps instruction for insufficiently aligned local on stack

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=7567

           Summary: clang generates movaps instruction for insufficiently
                    aligned local on stack
           Product: clang
           Version: trunk
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: LLVM Codegen
        AssignedTo: unassignedclangbugs at nondot.org
        ReportedBy: jay.foad at gmail.com
                CC: llvmbugs at cs.uiuc.edu


If I compile this source:

typedef __attribute__ ((aligned(16))) struct { unsigned long long x[2]; } L;
int one(L x);
int two(L x, L y) { return one(x) || one(y); }

with "clang -cc1 -S", I get:

two:
        subq    $88, %rsp
        movq    %rdi, 72(%rsp)
        movq    %rsi, 80(%rsp)
        movq    %rdx, 56(%rsp)
        movq    %rcx, 64(%rsp)
        movaps  72(%rsp), %xmm0
        movaps  %xmm0, 32(%rsp)
...

Memory arguments to movaps are required to be 16-byte aligned, but the argument
"72(%rsp)" is only 8-byte aligned. This causes a segmentation fault at run
time.

I'm using LLVM and Clang built from trunk this morning, on Ubuntu 10.4 64-bit.

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