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The current code normalizes select(C0, x, select(C1, x, y)) towards select(C0|C1, x, y) if the targets prefers that form. This patch adds an additional rule that if the select(C1, x, y) part already exists in the function then we want to normalize into the other direction because the effects of reusing the existing value are bigger than transforming into the target preferred form. This addresses regressions following r238793, see also: http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150727/290272.html Differential Revision: http://reviews.llvm.org/D11616 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245350 91177308-0d34-0410-b5e6-96231b3b80d8
48 lines
1.6 KiB
LLVM
48 lines
1.6 KiB
LLVM
; RUN: llc -o - %s | FileCheck %s
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target triple = "arm64--"
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@out = internal global i32 0, align 4
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; Ensure that we transform select(C0, x, select(C1, x, y)) towards
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; select(C0 | C1, x, y) so we can use CMP;CCMP for the implementation.
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; CHECK-LABEL: test0:
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; CHECK: cmp w0, #7
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; CHECK: ccmp w1, #0, #0, ne
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; CHECK: csel w0, w1, w2, gt
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; CHECK: ret
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define i32 @test0(i32 %v0, i32 %v1, i32 %v2) {
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%cmp1 = icmp eq i32 %v0, 7
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%cmp2 = icmp sgt i32 %v1, 0
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%sel0 = select i1 %cmp1, i32 %v1, i32 %v2
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%sel1 = select i1 %cmp2, i32 %v1, i32 %sel0
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ret i32 %sel1
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}
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; Usually we keep select(C0 | C1, x, y) as is on aarch64 to create CMP;CCMP
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; sequences. This case should be transformed to select(C0, select(C1, x, y), y)
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; anyway to get CSE effects.
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; CHECK-LABEL: test1:
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; CHECK-NOT: ccmp
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; CHECK: cmp w0, #7
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; CHECK: adrp x[[OUTNUM:[0-9]+]], out
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; CHECK: csel w[[SEL0NUM:[0-9]+]], w1, w2, eq
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; CHECK: cmp w[[SEL0NUM]], #13
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; CHECK: csel w[[SEL1NUM:[0-9]+]], w1, w2, lo
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; CHECK: cmp w0, #42
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; CHECK: csel w[[SEL2NUM:[0-9]+]], w1, w[[SEL1NUM]], eq
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; CHECK: str w[[SEL1NUM]], [x[[OUTNUM]], :lo12:out]
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; CHECK: str w[[SEL2NUM]], [x[[OUTNUM]], :lo12:out]
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; CHECK: ret
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define void @test1(i32 %bitset, i32 %val0, i32 %val1) {
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%cmp1 = icmp eq i32 %bitset, 7
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%cond = select i1 %cmp1, i32 %val0, i32 %val1
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%cmp5 = icmp ult i32 %cond, 13
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%cond11 = select i1 %cmp5, i32 %val0, i32 %val1
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%cmp3 = icmp eq i32 %bitset, 42
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%or.cond = or i1 %cmp3, %cmp5
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%cond17 = select i1 %or.cond, i32 %val0, i32 %val1
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store volatile i32 %cond11, i32* @out, align 4
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store volatile i32 %cond17, i32* @out, align 4
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ret void
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}
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