forked from OSchip/llvm-project
52 lines
1.6 KiB
LLVM
52 lines
1.6 KiB
LLVM
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; RUN: opt < %s -instcombine -S | FileCheck %s
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; Remove an icmp by using its operand in the subsequent logic directly.
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define i8 @zext_or_icmp_icmp(i8 %a, i8 %b) {
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%mask = and i8 %a, 1
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%toBool1 = icmp eq i8 %mask, 0
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%toBool2 = icmp eq i8 %b, 0
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%bothCond = or i1 %toBool1, %toBool2
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%zext = zext i1 %bothCond to i8
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ret i8 %zext
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; CHECK-LABEL: zext_or_icmp_icmp(
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; CHECK-NEXT: %mask = and i8 %a, 1
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; CHECK-NEXT: %toBool2 = icmp eq i8 %b, 0
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; CHECK-NEXT: %toBool22 = zext i1 %toBool2 to i8
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; CHECK-NEXT: %1 = xor i8 %mask, 1
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; CHECK-NEXT: %zext = or i8 %1, %toBool22
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; CHECK-NEXT: ret i8 %zext
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}
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; Here, widening the or from i1 to i32 and removing one of the icmps would
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; widen an undef value (created by the out-of-range shift), increasing the
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; range of valid values for the return, so we can't do it.
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define i32 @dont_widen_undef() {
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entry:
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br label %block2
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block1:
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br label %block2
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block2:
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%m.011 = phi i32 [ 33, %entry ], [ 0, %block1 ]
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%cmp.i = icmp ugt i32 %m.011, 1
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%m.1.op = lshr i32 1, %m.011
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%sext.mask = and i32 %m.1.op, 65535
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%cmp115 = icmp ne i32 %sext.mask, 0
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%cmp1 = or i1 %cmp.i, %cmp115
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%conv2 = zext i1 %cmp1 to i32
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ret i32 %conv2
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; CHECK-LABEL: dont_widen_undef(
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; CHECK: %m.011 = phi i32 [ 33, %entry ], [ 0, %block1 ]
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; CHECK-NEXT: %cmp.i = icmp ugt i32 %m.011, 1
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; CHECK-NEXT: %m.1.op = lshr i32 1, %m.011
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; CHECK-NEXT: %sext.mask = and i32 %m.1.op, 65535
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; CHECK-NEXT: %cmp115 = icmp ne i32 %sext.mask, 0
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; CHECK-NEXT: %cmp1 = or i1 %cmp.i, %cmp115
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; CHECK-NEXT: %conv2 = zext i1 %cmp1 to i32
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; CHECK-NEXT: ret i32 %conv2
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}
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