9deee6bffa
D141386 changed the semantics of !range metadata to return poison
on violation. If !range is combined with !noundef, violation is
immediate UB instead, matching the old semantics.
In theory, these IR semantics should also carry over into SDAG.
In practice, DAGCombine has at least one key transform that is
invalid in the presence of poison, namely the conversion of logical
and/or to bitwise and/or (c7b537bf09/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (L11252)).
Ideally, we would fix this transform, but this will require
substantial work to avoid codegen regressions.
In the meantime, avoid transferring !range metadata without
!noundef, effectively restoring the old !range metadata semantics
on the SDAG layer.
Fixes https://github.com/llvm/llvm-project/issues/64589.
Differential Revision: https://reviews.llvm.org/D157685
59 lines
1.4 KiB
LLVM
59 lines
1.4 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
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define zeroext i1 @f1(ptr %x) {
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; CHECK-LABEL: f1:
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; CHECK: ## %bb.0: ## %entry
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; CHECK-NEXT: movzbl (%rdi), %eax
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; CHECK-NEXT: retq
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entry:
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%0 = load i8, ptr %x, align 1, !range !0, !noundef !{}
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%tobool = trunc i8 %0 to i1
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ret i1 %tobool
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}
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define zeroext i1 @f2(ptr %x) {
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; CHECK-LABEL: f2:
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; CHECK: ## %bb.0: ## %entry
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; CHECK-NEXT: movzbl (%rdi), %eax
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; CHECK-NEXT: retq
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entry:
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%0 = load i8, ptr %x, align 1, !range !0, !noundef !{}
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%tobool = icmp ne i8 %0, 0
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ret i1 %tobool
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}
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!0 = !{i8 0, i8 2}
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; check that we don't build a "trunc" from i1 to i1, which would assert.
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define zeroext i1 @f3(i1 %x) {
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; CHECK-LABEL: f3:
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; CHECK: ## %bb.0: ## %entry
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: andb $1, %al
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; CHECK-NEXT: ## kill: def $al killed $al killed $eax
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; CHECK-NEXT: retq
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entry:
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%tobool = icmp ne i1 %x, 0
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ret i1 %tobool
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}
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; check that we don't build a trunc when other bits are needed
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define zeroext i1 @f4(i32 %x) {
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; CHECK-LABEL: f4:
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; CHECK: ## %bb.0: ## %entry
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; CHECK-NEXT: movzwl %di, %eax
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; CHECK-NEXT: shrl $15, %eax
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; CHECK-NEXT: ## kill: def $al killed $al killed $eax
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; CHECK-NEXT: retq
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entry:
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%y = and i32 %x, 32768
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%z = icmp ne i32 %y, 0
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ret i1 %z
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}
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