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| author | Evan Cheng <evan.cheng@apple.com> | 2008-06-25 20:52:59 +0000 |
|---|---|---|
| committer | Evan Cheng <evan.cheng@apple.com> | 2008-06-25 20:52:59 +0000 |
| commit | 57db53ba66a5d7dfc7361df50bdf635fa94f4743 (patch) | |
| tree | 701541c43568917524ac8ce65c7d11f29ac184d1 /lib/Target/X86/README-SSE.txt | |
| parent | 1568af892e006cb64363b5e2d23e1098005e7da2 (diff) | |
| download | external_llvm-57db53ba66a5d7dfc7361df50bdf635fa94f4743.zip external_llvm-57db53ba66a5d7dfc7361df50bdf635fa94f4743.tar.gz external_llvm-57db53ba66a5d7dfc7361df50bdf635fa94f4743.tar.bz2 | |
- Fix a x86 vector isel bug: illegal transformation of a vector_shuffle into a
shift.
- Add a readme entry for a missing vector_shuffle optimization that results in
awful codegen.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52740 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target/X86/README-SSE.txt')
| -rw-r--r-- | lib/Target/X86/README-SSE.txt | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/lib/Target/X86/README-SSE.txt b/lib/Target/X86/README-SSE.txt index ad28248..8714424 100644 --- a/lib/Target/X86/README-SSE.txt +++ b/lib/Target/X86/README-SSE.txt @@ -808,3 +808,34 @@ LC0: With SSE4, it should be movdqa .LC0(%rip), %xmm0 pinsrb $6, %edi, %xmm0 + +//===---------------------------------------------------------------------===// + +We should transform a shuffle of two vectors of constants into a single vector +of constants. Also, insertelement of a constant into a vector of constants +should also result in a vector of constants. e.g. 2008-06-25-VecISelBug.ll. + +We compiled it to something horrible: + + .align 4 +LCPI1_1: ## float + .long 1065353216 ## float 1 + .const + + .align 4 +LCPI1_0: ## <4 x float> + .space 4 + .long 1065353216 ## float 1 + .space 4 + .long 1065353216 ## float 1 + .text + .align 4,0x90 + .globl _t +_t: + xorps %xmm0, %xmm0 + movhps LCPI1_0, %xmm0 + movss LCPI1_1, %xmm1 + movaps %xmm0, %xmm2 + shufps $2, %xmm1, %xmm2 + shufps $132, %xmm2, %xmm0 + movaps %xmm0, 0 |