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| author | DianQK <dianqk@dianqk.net> | 2023-04-16 22:35:27 +0800 |
|---|---|---|
| committer | Tom Stellard <tstellar@redhat.com> | 2023-04-18 18:08:51 -0700 |
| commit | 18ddebe1a1a9bde349441631365f0472e9693520 (patch) | |
| tree | 3adebe002143ccfc0ca7adb638311f3bf6c3b38c | |
| parent | dbcd2e9330cd43921e13d8dce3d9b743ea2fe871 (diff) | |
| download | llvm-18ddebe1a1a9bde349441631365f0472e9693520.tar.gz | |
Remove UB-implying metadata when promoting speculative instruction.llvmorg-16.0.2
After D138238 introduced the then/else blocks, we should remove UB-implying metadata for the promoted speculative instruction.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D148456
(cherry picked from commit 2832d7941f4207f1fcf813b27cf08cecc3086959)
| -rw-r--r-- | llvm/lib/Transforms/Scalar/SROA.cpp | 6 | ||||
| -rw-r--r-- | llvm/test/Transforms/SROA/select-load.ll | 24 |
2 files changed, 28 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Scalar/SROA.cpp b/llvm/lib/Transforms/Scalar/SROA.cpp index 8339981e1bdc..818d64725893 100644 --- a/llvm/lib/Transforms/Scalar/SROA.cpp +++ b/llvm/lib/Transforms/Scalar/SROA.cpp @@ -1581,15 +1581,17 @@ static void rewriteMemOpOfSelect(SelectInst &SI, T &I, bool IsThen = SuccBB == HeadBI->getSuccessor(0); int SuccIdx = IsThen ? 0 : 1; auto *NewMemOpBB = SuccBB == Tail ? Head : SuccBB; + auto &CondMemOp = cast<T>(*I.clone()); if (NewMemOpBB != Head) { NewMemOpBB->setName(Head->getName() + (IsThen ? ".then" : ".else")); if (isa<LoadInst>(I)) ++NumLoadsPredicated; else ++NumStoresPredicated; - } else + } else { + CondMemOp.dropUndefImplyingAttrsAndUnknownMetadata(); ++NumLoadsSpeculated; - auto &CondMemOp = cast<T>(*I.clone()); + } CondMemOp.insertBefore(NewMemOpBB->getTerminator()); Value *Ptr = SI.getOperand(1 + SuccIdx); if (auto *PtrTy = Ptr->getType(); diff --git a/llvm/test/Transforms/SROA/select-load.ll b/llvm/test/Transforms/SROA/select-load.ll index aac7af93d219..7df72419b0ce 100644 --- a/llvm/test/Transforms/SROA/select-load.ll +++ b/llvm/test/Transforms/SROA/select-load.ll @@ -409,7 +409,31 @@ entry: ret i32 %r } +; When promoting speculative instruction, metadata that may trigger immediate UB should be dropped. +define void @load_of_select_with_noundef_nonnull(ptr %buffer, i1 %b) { +; CHECK-PRESERVE-CFG-LABEL: @load_of_select_with_noundef_nonnull( +; CHECK-PRESERVE-CFG-NEXT: [[UB_PTR:%.*]] = alloca ptr, align 8 +; CHECK-PRESERVE-CFG-NEXT: [[SELECT_PTR:%.*]] = select i1 [[B:%.*]], ptr [[BUFFER:%.*]], ptr [[UB_PTR]] +; CHECK-PRESERVE-CFG-NEXT: [[LOAD_PTR:%.*]] = load ptr, ptr [[SELECT_PTR]], align 8, !nonnull !1, !noundef !1 +; CHECK-PRESERVE-CFG-NEXT: ret void +; +; CHECK-MODIFY-CFG-LABEL: @load_of_select_with_noundef_nonnull( +; CHECK-MODIFY-CFG-NEXT: br i1 [[B:%.*]], label [[DOTTHEN:%.*]], label [[DOTCONT:%.*]] +; CHECK-MODIFY-CFG: .then: +; CHECK-MODIFY-CFG-NEXT: [[LOAD_PTR_THEN_VAL:%.*]] = load ptr, ptr [[BUFFER:%.*]], align 8, !nonnull !2, !noundef !2 +; CHECK-MODIFY-CFG-NEXT: br label [[DOTCONT]] +; CHECK-MODIFY-CFG: .cont: +; CHECK-MODIFY-CFG-NEXT: [[LOAD_PTR:%.*]] = phi ptr [ [[LOAD_PTR_THEN_VAL]], [[DOTTHEN]] ], [ undef, [[TMP0:%.*]] ] +; CHECK-MODIFY-CFG-NEXT: ret void +; + %ub_ptr = alloca ptr + %select_ptr = select i1 %b, ptr %buffer, ptr %ub_ptr + %load_ptr = load ptr, ptr %select_ptr, !nonnull !1, !noundef !1 + ret void +} + !0 = !{!"branch_weights", i32 1, i32 99} +!1 = !{} ; Ensure that the branch metadata is reversed to match the reversals above. |