diff options
| -rw-r--r-- | llvm/lib/Transforms/Scalar/GVN.cpp | 6 | ||||
| -rw-r--r-- | llvm/test/Transforms/GVN/condprop.ll | 72 |
2 files changed, 78 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp index c48e766c797..95c35adb8f5 100644 --- a/llvm/lib/Transforms/Scalar/GVN.cpp +++ b/llvm/lib/Transforms/Scalar/GVN.cpp @@ -1736,6 +1736,9 @@ bool GVN::propagateEquality(Value *LHS, Value *RHS, const BasicBlockEdge &Root, Changed |= NumReplacements > 0; NumGVNEqProp += NumReplacements; + // Cached information for anything that uses LHS will be invalid. + if (MD) + MD->invalidateCachedPointerInfo(LHS); } // Now try to deduce additional equalities from this one. For example, if @@ -1811,6 +1814,9 @@ bool GVN::propagateEquality(Value *LHS, Value *RHS, const BasicBlockEdge &Root, Root.getStart()); Changed |= NumReplacements > 0; NumGVNEqProp += NumReplacements; + // Cached information for anything that uses NotCmp will be invalid. + if (MD) + MD->invalidateCachedPointerInfo(NotCmp); } } // Ensure that any instruction in scope that gets the "A < B" value number diff --git a/llvm/test/Transforms/GVN/condprop.ll b/llvm/test/Transforms/GVN/condprop.ll index 6aa3cb86250..949fdd0c0c9 100644 --- a/llvm/test/Transforms/GVN/condprop.ll +++ b/llvm/test/Transforms/GVN/condprop.ll @@ -297,3 +297,75 @@ ret: ; CHECK: %res = phi i32 [ 0, %cond_true ], [ %x, %cond_false ] ret i32 %res } + +; On the path from entry->if->end we know that ptr1==ptr2, so we can determine +; that gep2 does not alias ptr1 on that path (as it would require that +; ptr2==ptr2+2), so we can perform PRE of the load. +; CHECK-LABEL: @test13 +define i32 @test13(i32* %ptr1, i32* %ptr2) { +; CHECK-LABEL: entry: +entry: + %gep1 = getelementptr i32, i32* %ptr2, i32 1 + %gep2 = getelementptr i32, i32* %ptr2, i32 2 + %cmp = icmp eq i32* %ptr1, %ptr2 + br i1 %cmp, label %if, label %end + +; CHECK: [[CRIT_EDGE:.*]]: +; CHECK: %[[PRE:.*]] = load i32, i32* %gep2, align 4 + +; CHECK-LABEL: if: +if: + %val1 = load i32, i32* %gep2, align 4 + br label %end + +; CHECK-LABEL: end: +; CHECK: %val2 = phi i32 [ %val1, %if ], [ %[[PRE]], %[[CRIT_EDGE]] ] +; CHECK-NOT: load +end: + %phi1 = phi i32* [ %ptr1, %if ], [ %gep1, %entry ] + %phi2 = phi i32 [ %val1, %if ], [ 0, %entry ] + store i32 0, i32* %phi1, align 4 + %val2 = load i32, i32* %gep2, align 4 + %ret = add i32 %phi2, %val2 + ret i32 %ret +} + +; CHECK-LABEL: @test14 +define void @test14(i32* %ptr1, i32* noalias %ptr2) { +entry: + %gep1 = getelementptr inbounds i32, i32* %ptr1, i32 1 + %gep2 = getelementptr inbounds i32, i32* %ptr1, i32 2 + br label %loop + +; CHECK-LABEL: loop: +loop: + %phi1 = phi i32* [ %gep3, %loop.end ], [ %gep1, %entry ] + br i1 undef, label %if1, label %then + +; CHECK: [[CRIT_EDGE:.*]]: +; CHECK: %[[PRE:.*]] = load i32, i32* %gep2, align 4 + +; CHECK-LABEL: if1: +; CHECK: %val2 = phi i32 [ %[[PRE]], %[[CRIT_EDGE]] ], [ %val3, %loop.end ] +; CHECK-NOT: load +if1: + %val2 = load i32, i32* %gep2, align 4 + store i32 %val2, i32* %gep2, align 4 + store i32 0, i32* %phi1, align 4 + br label %then + +; CHECK-LABEL: then: +then: + %cmp = icmp eq i32* %gep2, %ptr2 + br i1 %cmp, label %loop.end, label %if2 + +if2: + br label %loop.end + +loop.end: + %phi3 = phi i32* [ %gep2, %then ], [ %ptr1, %if2 ] + %val3 = load i32, i32* %gep2, align 4 + store i32 %val3, i32* %phi3, align 4 + %gep3 = getelementptr inbounds i32, i32* %ptr1, i32 1 + br i1 undef, label %loop, label %if1 +} |
