diff options
| -rw-r--r-- | lib/Analysis/LoopInfo.cpp | 7 | ||||
| -rw-r--r-- | lib/Transforms/Scalar/LICM.cpp | 4 | ||||
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 5 | ||||
| -rw-r--r-- | test/Analysis/TypeBasedAliasAnalysis/licm.ll | 2 | ||||
| -rw-r--r-- | test/Transforms/LICM/hoist-deref-load.ll | 44 | ||||
| -rw-r--r-- | test/Transforms/SimplifyCFG/SpeculativeExec.ll | 26 |
6 files changed, 87 insertions, 1 deletions
diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp index 9ee72361c92..e679b7ad7b8 100644 --- a/lib/Analysis/LoopInfo.cpp +++ b/lib/Analysis/LoopInfo.cpp @@ -120,6 +120,13 @@ bool Loop::makeLoopInvariant(Instruction *I, bool &Changed, // Hoist. I->moveBefore(InsertPt); + + // There is possibility of hoisting this instruction above some arbitrary + // condition. Any metadata defined on it can be control dependent on this + // condition. Conservatively strip it here so that we don't give any wrong + // information to the optimizer. + I->dropUnknownNonDebugMetadata(); + Changed = true; return true; } diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp index ba39afd4287..6d70cdc3ade 100644 --- a/lib/Transforms/Scalar/LICM.cpp +++ b/lib/Transforms/Scalar/LICM.cpp @@ -672,6 +672,10 @@ static bool hoist(Instruction &I, BasicBlock *Preheader) { // Move the new node to the Preheader, before its terminator. I.moveBefore(Preheader->getTerminator()); + // Metadata can be dependent on the condition we are hoisting above. + // Conservatively strip all metadata on the instruction. + I.dropUnknownNonDebugMetadata(); + if (isa<LoadInst>(I)) ++NumMovedLoads; else if (isa<CallInst>(I)) ++NumMovedCalls; ++NumHoisted; diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index e0c598f92e2..ff81e7d5acf 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -1618,6 +1618,11 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB, SpeculatedStore->setOperand(0, S); } + // Metadata can be dependent on the condition we are hoisting above. + // Conservatively strip all metadata on the instruction. + for (auto &I: *ThenBB) + I.dropUnknownNonDebugMetadata(); + // Hoist the instructions. BB->getInstList().splice(BI->getIterator(), ThenBB->getInstList(), ThenBB->begin(), std::prev(ThenBB->end())); diff --git a/test/Analysis/TypeBasedAliasAnalysis/licm.ll b/test/Analysis/TypeBasedAliasAnalysis/licm.ll index fe07730577e..d2aee58204d 100644 --- a/test/Analysis/TypeBasedAliasAnalysis/licm.ll +++ b/test/Analysis/TypeBasedAliasAnalysis/licm.ll @@ -5,7 +5,7 @@ ; CHECK: @foo ; CHECK: entry: -; CHECK-NEXT: %tmp3 = load double*, double** @P, !tbaa !0 +; CHECK-NEXT: %tmp3 = load double*, double** @P ; CHECK-NEXT: br label %for.body @P = common global double* null diff --git a/test/Transforms/LICM/hoist-deref-load.ll b/test/Transforms/LICM/hoist-deref-load.ll index c384a858d1e..fd10c5d7503 100644 --- a/test/Transforms/LICM/hoist-deref-load.ll +++ b/test/Transforms/LICM/hoist-deref-load.ll @@ -388,5 +388,49 @@ for.end: ; preds = %for.inc, %entry ret void } +; In this test we should be able to only hoist load from %cptr. We can't hoist +; load from %c because it's dereferenceability can depend on %cmp1 condition. +; By moving it out of the loop we break this dependency and can not rely +; on the dereferenceability anymore. +; In other words this test checks that we strip dereferenceability metadata +; after hoisting an instruction. + +; CHECK-LABEL: @test10 +; CHECK: %c = load i32*, i32** %cptr +; CHECK-NOT: dereferenceable +; CHECK: if.then: +; CHECK: load i32, i32* %c, align 4 + +define void @test10(i32* noalias %a, i32* %b, i32** dereferenceable(8) %cptr, i32 %n) #0 { +entry: + %cmp11 = icmp sgt i32 %n, 0 + br i1 %cmp11, label %for.body, label %for.end + +for.body: ; preds = %entry, %for.inc + %indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %entry ] + %arrayidx = getelementptr inbounds i32, i32* %a, i64 %indvars.iv + %0 = load i32, i32* %arrayidx, align 4 + %cmp1 = icmp sgt i32 %0, 0 + br i1 %cmp1, label %if.then, label %for.inc + +if.then: ; preds = %for.body + %c = load i32*, i32** %cptr, !dereferenceable !0 + %1 = load i32, i32* %c, align 4 + %arrayidx3 = getelementptr inbounds i32, i32* %b, i64 %indvars.iv + %2 = load i32, i32* %arrayidx3, align 4 + %mul = mul nsw i32 %2, %1 + store i32 %mul, i32* %arrayidx, align 4 + br label %for.inc + +for.inc: ; preds = %for.body, %if.then + %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 + %lftr.wideiv = trunc i64 %indvars.iv.next to i32 + %exitcond = icmp eq i32 %lftr.wideiv, %n + br i1 %exitcond, label %for.end, label %for.body + +for.end: ; preds = %for.inc, %entry + ret void +} + attributes #0 = { nounwind uwtable } !0 = !{i64 4} diff --git a/test/Transforms/SimplifyCFG/SpeculativeExec.ll b/test/Transforms/SimplifyCFG/SpeculativeExec.ll index c23a96df52e..73f9a0f88ac 100644 --- a/test/Transforms/SimplifyCFG/SpeculativeExec.ll +++ b/test/Transforms/SimplifyCFG/SpeculativeExec.ll @@ -69,3 +69,29 @@ end: ret i8* %x10 } + +define i32* @test5(i32 %a, i32 %b, i32 %c, i32* dereferenceable(10) %ptr1, + i32* dereferenceable(10) %ptr2, i32** dereferenceable(10) %ptr3) nounwind { +; CHECK-LABEL: @test5( +entry: + %tmp1 = icmp eq i32 %b, 0 + br i1 %tmp1, label %bb1, label %bb3 + +bb1: ; preds = %entry + %tmp2 = icmp sgt i32 %c, 1 + br i1 %tmp2, label %bb2, label %bb3 +; CHECK: bb1: +; CHECK-NEXT: icmp sgt i32 %c, 1 +; CHECK-NEXT: load i32*, i32** %ptr3 +; CHECK-NOT: dereferenceable +; CHECK-NEXT: select i1 %tmp2, i32* %tmp3, i32* %ptr2 +; CHECK-NEXT: ret i32* %tmp3.ptr2 + +bb2: ; preds = bb1 + %tmp3 = load i32*, i32** %ptr3, !dereferenceable !{i64 10} + br label %bb3 + +bb3: ; preds = %bb2, %entry + %tmp4 = phi i32* [ %ptr1, %entry ], [ %ptr2, %bb1 ], [ %tmp3, %bb2 ] + ret i32* %tmp4 +} |