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This is a first step towards canonicalization and improved folding/codegen for integer min/max as discussed here: http://lists.llvm.org/pipermail/llvm-dev/2016-November/106868.html Here, we're just matching the simplest min/max patterns and adjusting the icmp predicate while swapping the select operands. I've included FIXME tests in test/Transforms/InstCombine/select_meta.ll so it's easier to see how this might be extended (corresponds to the TODO comment in the code). That's also why I'm using matchSelectPattern() rather than a simpler check; once the backend is patched, we can just remove some of the restrictions to allow the obfuscated min/max patterns in the FIXME tests to be matched. Differential Revision: https://reviews.llvm.org/D26525 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287585 91177308-0d34-0410-b5e6-96231b3b80d8
21 lines
769 B
LLVM
21 lines
769 B
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt -S -instcombine < %s | FileCheck %s
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define float @test1(i32 %scale) {
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; CHECK-LABEL: @test1(
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; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i32 %scale, 1
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; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 %scale, i32 1
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; CHECK-NEXT: [[TMP3:%.*]] = sitofp i32 [[TMP2]] to float
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; CHECK-NEXT: [[TMP4:%.*]] = icmp sgt i32 [[TMP2]], 0
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; CHECK-NEXT: [[SEL:%.*]] = select i1 [[TMP4]], float [[TMP3]], float 0.000000e+00
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; CHECK-NEXT: ret float [[SEL]]
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;
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%tmp1 = icmp sgt i32 1, %scale
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%tmp2 = select i1 %tmp1, i32 1, i32 %scale
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%tmp3 = sitofp i32 %tmp2 to float
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%tmp4 = icmp sgt i32 %tmp2, 0
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%sel = select i1 %tmp4, float %tmp3, float 0.000000e+00
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ret float %sel
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}
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