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| author | Jim Grosbach <grosbach@apple.com> | 2013-11-22 19:57:47 +0000 |
|---|---|---|
| committer | Jim Grosbach <grosbach@apple.com> | 2013-11-22 19:57:47 +0000 |
| commit | 860934a9240309e18f92152e8eec130b5b46d8a0 (patch) | |
| tree | 5dcc70c5a0273883120a56cf870c9219b178c007 /llvm/test/CodeGen/X86/memcmp.ll | |
| parent | 4b7f23d885d87274441a108336b7b328284addf4 (diff) | |
| download | bcm5719-llvm-860934a9240309e18f92152e8eec130b5b46d8a0.tar.gz bcm5719-llvm-860934a9240309e18f92152e8eec130b5b46d8a0.zip | |
X86: Perform integer comparisons at i32 or larger.
Utilizing the 8 and 16 bit comparison instructions, even when an input can
be folded into the comparison instruction itself, is typically not worth it.
There are too many partial register stalls as a result, leading to significant
slowdowns. By always performing comparisons on at least 32-bit
registers, performance of the calculation chain leading to the
comparison improves. Continue to use the smaller comparisons when
minimizing size, as that allows better folding of loads into the
comparison instructions.
rdar://15386341
llvm-svn: 195496
Diffstat (limited to 'llvm/test/CodeGen/X86/memcmp.ll')
| -rw-r--r-- | llvm/test/CodeGen/X86/memcmp.ll | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/llvm/test/CodeGen/X86/memcmp.ll b/llvm/test/CodeGen/X86/memcmp.ll index cb0797d3eb3..0a534926c6c 100644 --- a/llvm/test/CodeGen/X86/memcmp.ll +++ b/llvm/test/CodeGen/X86/memcmp.ll @@ -22,8 +22,9 @@ bb: ; preds = %entry return: ; preds = %entry ret void ; CHECK-LABEL: memcmp2: -; CHECK: movw ([[A0:%rdi|%rcx]]), %ax -; CHECK: cmpw ([[A1:%rsi|%rdx]]), %ax +; CHECK: movzwl +; CHECK-NEXT: movzwl +; CHECK-NEXT: cmpl ; NOBUILTIN-LABEL: memcmp2: ; NOBUILTIN: callq } @@ -41,7 +42,8 @@ bb: ; preds = %entry return: ; preds = %entry ret void ; CHECK-LABEL: memcmp2a: -; CHECK: cmpw $28527, ([[A0]]) +; CHECK: movzwl +; CHECK-NEXT: cmpl $28527, } @@ -58,8 +60,8 @@ bb: ; preds = %entry return: ; preds = %entry ret void ; CHECK-LABEL: memcmp4: -; CHECK: movl ([[A0]]), %eax -; CHECK: cmpl ([[A1]]), %eax +; CHECK: movl +; CHECK-NEXT: cmpl } define void @memcmp4a(i8* %X, i32* nocapture %P) nounwind { @@ -75,7 +77,7 @@ bb: ; preds = %entry return: ; preds = %entry ret void ; CHECK-LABEL: memcmp4a: -; CHECK: cmpl $1869573999, ([[A0]]) +; CHECK: cmpl $1869573999, } define void @memcmp8(i8* %X, i8* %Y, i32* nocapture %P) nounwind { @@ -91,8 +93,8 @@ bb: ; preds = %entry return: ; preds = %entry ret void ; CHECK-LABEL: memcmp8: -; CHECK: movq ([[A0]]), %rax -; CHECK: cmpq ([[A1]]), %rax +; CHECK: movq +; CHECK: cmpq } define void @memcmp8a(i8* %X, i32* nocapture %P) nounwind { @@ -108,7 +110,7 @@ bb: ; preds = %entry return: ; preds = %entry ret void ; CHECK-LABEL: memcmp8a: -; CHECK: movabsq $8029759185026510694, %rax -; CHECK: cmpq %rax, ([[A0]]) +; CHECK: movabsq $8029759185026510694, +; CHECK: cmpq } |
