060de415af
Relative to the first attempt, this contains two changes: First, we only handle the case where one side simplifies to true or false, instead of calling simplification recursively. The previous approach would return poison if one operand simplified to poison (under the equality assumption), which is incorrect. Second, we do not fold llvm.is.constant in simplifyWithOpReplaced(). We may be assuming that a value is constant, if the equality holds, but it may not actually be constant. This is nominally just a QoI issue, but the std::list implementation in libstdc++ relies on the precise behavior in a way that causes miscompiles. ----- and/or in logical (select) form benefit from generic simplifications via simplifyWithOpReplaced(). However, the corresponding fold for plain and/or currently does not exist. Similar to selects, there are two general cases for this fold (illustrated with `and`, but there are `or` conjugates). The basic case is something like `(a == b) & c`, where the replacement of a with b or b with a inside c allows it to fold to true or false. Then the whole operation will fold to either false or `a == b`. The second case is something like `(a != b) & c`, where the replacement inside c allows it to fold to false. In that case, the operand can be replaced with c, because in the case where a == b (and thus the icmp is false), c itself will already be false. As the test diffs show, this catches quite a lot of patterns in existing test coverage. This also obsoletes quite a few existing special-case and/or of icmp folds we have (e.g. simplifyAndOrOfICmpsWithLimitConst), but I haven't removed anything as part of this patch in the interest of risk mitigation. Fixes #69050. Fixes #69091.
83 lines
2.7 KiB
LLVM
83 lines
2.7 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu \
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; RUN: -mcpu=pwr9 -ppc-asm-full-reg-names -ppc-vsr-nums-as-vr < %s | \
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; RUN: FileCheck %s
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define hidden void @julia_tryparse_internal_45896() #0 {
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; CHECK-LABEL: julia_tryparse_internal_45896:
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; CHECK: # %bb.0: # %top
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; CHECK-NEXT: ld r3, 0(r3)
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; CHECK-NEXT: cmpldi r3, 0
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; CHECK-NEXT: beq cr0, .LBB0_6
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; CHECK-NEXT: # %bb.1: # %top
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; CHECK-NEXT: cmpldi r3, 10
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; CHECK-NEXT: beq cr0, .LBB0_3
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; CHECK-NEXT: # %bb.2: # %top
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; CHECK-NEXT: .LBB0_3: # %L294
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; CHECK-NEXT: bc 12, 4*cr5+lt, .LBB0_5
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; CHECK-NEXT: # %bb.4: # %L294
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; CHECK-NEXT: bc 4, 4*cr5+lt, .LBB0_7
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; CHECK-NEXT: .LBB0_5: # %L1057.preheader
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; CHECK-NEXT: .LBB0_6: # %fail194
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; CHECK-NEXT: .LBB0_7: # %L670
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; CHECK-NEXT: li r5, -3
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; CHECK-NEXT: sradi r4, r3, 63
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; CHECK-NEXT: rldic r5, r5, 4, 32
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; CHECK-NEXT: mulhdu r3, r3, r5
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; CHECK-NEXT: maddld r6, r4, r5, r3
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; CHECK-NEXT: cmpld cr1, r6, r3
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; CHECK-NEXT: mulhdu. r3, r4, r5
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; CHECK-NEXT: crorc 4*cr5+lt, 4*cr1+lt, eq
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; CHECK-NEXT: bc 4, 4*cr5+lt, .LBB0_9
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; CHECK-NEXT: # %bb.8: # %L917
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; CHECK-NEXT: .LBB0_9: # %L994
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top:
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%0 = load i64, ptr undef, align 8
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%1 = icmp ne i64 %0, 0
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%2 = sext i64 %0 to i128
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switch i64 %0, label %pass195 [
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i64 10, label %L294
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i64 16, label %L294.fold.split
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i64 0, label %fail194
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]
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L294.fold.split: ; preds = %top
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unreachable
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L294: ; preds = %top
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%3 = add nsw i32 0, -48
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%4 = zext i32 %3 to i128
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%5 = add i128 %4, 0
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switch i32 undef, label %L670 [
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i32 -1031471104, label %L1057.preheader
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i32 536870912, label %L1057.preheader
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]
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L670: ; preds = %L294
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br label %L898
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L1057.preheader: ; preds = %L294, %L294
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unreachable
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L898: ; preds = %L670
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%umul = call { i128, i1 } @llvm.umul.with.overflow.i128(i128 %2, i128 %5)
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%umul.ov = extractvalue { i128, i1 } %umul, 1
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%value_phi102 = and i1 %1, %umul.ov
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%6 = or i1 %value_phi102, false
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br i1 %6, label %L917, label %L994
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L917: ; preds = %L898
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unreachable
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L994: ; preds = %L898
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unreachable
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fail194: ; preds = %top
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unreachable
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pass195: ; preds = %top
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unreachable
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}
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; Function Attrs: nounwind readnone speculatable willreturn
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declare { i128, i1 } @llvm.umul.with.overflow.i128(i128, i128) #1
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