e44b11d9b6
We were already treating branch on poison as UB, but branch on undef is also UB. Move the checks into the correct function. From LangRef for br: > If ‘cond’ is poison or undef, this instruction has undefined behavior. From LangRef for switch: > If ‘value’ is poison or undef, this instruction has undefined behavior. There is a minor regression in dont-distribute-phi.ll, apparently we handle that pattern in logical but not bitwise form.
80 lines
2.2 KiB
LLVM
80 lines
2.2 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -passes=instcombine -S | FileCheck %s
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;
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; This test ensures that InstCombine does not distribute And over Xor
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; using simplifications involving undef.
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define zeroext i1 @foo(i32 %arg) {
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; CHECK-LABEL: @foo(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[ARG:%.*]], 37
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; CHECK-NEXT: br i1 [[CMP1]], label [[BB_ELSE:%.*]], label [[BB_THEN:%.*]]
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; CHECK: bb_then:
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; CHECK-NEXT: call void @bar()
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; CHECK-NEXT: br label [[BB_EXIT:%.*]]
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; CHECK: bb_else:
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; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[ARG]], 17
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; CHECK-NEXT: br label [[BB_EXIT]]
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; CHECK: bb_exit:
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; CHECK-NEXT: [[PHI1:%.*]] = phi i1 [ [[CMP2]], [[BB_ELSE]] ], [ undef, [[BB_THEN]] ]
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; CHECK-NEXT: [[AND1:%.*]] = and i1 [[PHI1]], [[CMP1]]
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; CHECK-NEXT: ret i1 [[AND1]]
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;
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entry:
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%cmp1 = icmp eq i32 %arg, 37
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br i1 %cmp1, label %bb_then, label %bb_else
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bb_then:
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call void @bar()
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br label %bb_exit
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bb_else:
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%cmp2 = icmp slt i32 %arg, 17
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br label %bb_exit
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bb_exit:
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%phi1 = phi i1 [ %cmp2, %bb_else ], [ undef, %bb_then ]
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%xor1 = xor i1 %cmp1, true
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%and1 = and i1 %phi1, %xor1
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ret i1 %and1
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}
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define zeroext i1 @foo_logical(i32 %arg) {
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; CHECK-LABEL: @foo_logical(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[ARG:%.*]], 37
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; CHECK-NEXT: br i1 [[CMP1]], label [[BB_ELSE:%.*]], label [[BB_THEN:%.*]]
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; CHECK: bb_then:
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; CHECK-NEXT: call void @bar()
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; CHECK-NEXT: br label [[BB_EXIT:%.*]]
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; CHECK: bb_else:
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; CHECK-NEXT: [[CMP2:%.*]] = icmp slt i32 [[ARG]], 17
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; CHECK-NEXT: br label [[BB_EXIT]]
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; CHECK: bb_exit:
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; CHECK-NEXT: [[PHI1:%.*]] = phi i1 [ [[CMP2]], [[BB_ELSE]] ], [ undef, [[BB_THEN]] ]
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; CHECK-NEXT: [[AND1:%.*]] = and i1 [[PHI1]], [[CMP1]]
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; CHECK-NEXT: ret i1 [[AND1]]
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;
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entry:
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%cmp1 = icmp eq i32 %arg, 37
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br i1 %cmp1, label %bb_then, label %bb_else
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bb_then:
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call void @bar()
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br label %bb_exit
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bb_else:
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%cmp2 = icmp slt i32 %arg, 17
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br label %bb_exit
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bb_exit:
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%phi1 = phi i1 [ %cmp2, %bb_else ], [ undef, %bb_then ]
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%xor1 = xor i1 %cmp1, true
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%and1 = select i1 %phi1, i1 %xor1, i1 false
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ret i1 %and1
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}
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declare void @bar()
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