d9e92765c5
`ConstantRange::binaryXor` gives poor results as it currently depends on `KnownBits::operator^`. Since `sub A, B` is canonicalized into `xor A, B` if `B` is the subset of `A`, this patch reverts the transform in `ConstantRange::binaryXor`, which will give better results. Alive2: https://alive2.llvm.org/ce/z/bmTMV9 Fixes #79696.
56 lines
1.8 KiB
LLVM
56 lines
1.8 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
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; RUN: opt < %s -passes=ipsccp -S | FileCheck %s
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; Tests from PR79696
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define i1 @constant_range_xor(i64 %a) {
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; CHECK-LABEL: define i1 @constant_range_xor(
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; CHECK-SAME: i64 [[A:%.*]]) {
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i64 [[A]], 8192
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; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
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; CHECK: then:
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; CHECK-NEXT: [[CTLZ:%.*]] = call i64 @llvm.ctlz.i64(i64 [[A]], i1 true)
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; CHECK-NEXT: [[CONV:%.*]] = xor i64 [[CTLZ]], 63
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; CHECK-NEXT: ret i1 false
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; CHECK: else:
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; CHECK-NEXT: ret i1 false
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;
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entry:
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%cmp = icmp ugt i64 %a, 8192
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br i1 %cmp, label %then, label %else
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then:
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%ctlz = call i64 @llvm.ctlz.i64(i64 %a, i1 true) ;[0, 50]
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%conv = xor i64 %ctlz, 63 ;[13, 63]
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%cmp1 = icmp ult i64 %conv, 13
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ret i1 %cmp1
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else:
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ret i1 false
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}
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define i1 @constant_range_xor_negative(i64 %a) {
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; CHECK-LABEL: define i1 @constant_range_xor_negative(
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; CHECK-SAME: i64 [[A:%.*]]) {
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i64 [[A]], 8192
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; CHECK-NEXT: br i1 [[CMP]], label [[THEN:%.*]], label [[ELSE:%.*]]
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; CHECK: then:
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; CHECK-NEXT: [[CTLZ:%.*]] = call i64 @llvm.ctlz.i64(i64 [[A]], i1 true)
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; CHECK-NEXT: [[CONV:%.*]] = xor i64 [[CTLZ]], 62
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; CHECK-NEXT: [[CMP1:%.*]] = icmp ult i64 [[CONV]], 13
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; CHECK-NEXT: ret i1 [[CMP1]]
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; CHECK: else:
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; CHECK-NEXT: ret i1 false
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;
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entry:
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%cmp = icmp ugt i64 %a, 8192
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br i1 %cmp, label %then, label %else
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then:
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%ctlz = call i64 @llvm.ctlz.i64(i64 %a, i1 true) ;[0, 50]
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%conv = xor i64 %ctlz, 62 ;[12, 63]
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%cmp1 = icmp ult i64 %conv, 13
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ret i1 %cmp1
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else:
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ret i1 false
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}
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