llvm/test/CodeGen/X86/fast-isel-select.ll
Juergen Ributzka 5f4e6e1ec0 [FastISel][X86] Optimize selects when the condition comes from a compare.
Optimize the select instructions sequence to use the EFLAGS directly from a
compare when possible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211543 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-23 21:55:36 +00:00

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637 B
LLVM

; RUN: llc -mtriple x86_64-apple-darwin -O0 -o - < %s | FileCheck %s
; Make sure we only use the less significant bit of the value that feeds the
; select. Otherwise, we may account for a non-zero value whereas the
; lsb is zero.
; <rdar://problem/15651765>
; CHECK-LABEL: fastisel_select:
; CHECK: subb {{%[a-z0-9]+}}, [[RES:%[a-z0-9]+]]
; CHECK: testb $1, [[RES]]
; CHECK: cmovnel %edi, %esi
define i32 @fastisel_select(i1 %exchSub2211_, i1 %trunc_8766) {
%shuffleInternal15257_8932 = sub i1 %exchSub2211_, %trunc_8766
%counter_diff1345 = select i1 %shuffleInternal15257_8932, i32 1204476887, i32 0
ret i32 %counter_diff1345
}