diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 34a0e04bc05..2b65cce970c 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -9858,6 +9858,17 @@ SDValue DAGCombiner::visitSTORE(SDNode *N) { } } + // If this is a store followed by a store with the same value to the same + // location, then the store is dead/noop. + if (StoreSDNode *ST1 = dyn_cast<StoreSDNode>(Chain)) { + if (ST1->getBasePtr() == Ptr && ST->getMemoryVT() == ST1->getMemoryVT() && + ST1->getValue() == Value && ST->isUnindexed() && !ST->isVolatile() && + ST1->isUnindexed() && !ST1->isVolatile()) { + // The store is dead, remove it. + return Chain; + } + } + // If this is an FP_ROUND or TRUNC followed by a store, fold this into a // truncating store. We can do this even if this is already a truncstore. if ((Value.getOpcode() == ISD::FP_ROUND || Value.getOpcode() == ISD::TRUNCATE) diff --git a/test/CodeGen/AArch64/Redundantstore.ll b/test/CodeGen/AArch64/Redundantstore.ll new file mode 100644 index 00000000000..72f7f4679e6 --- /dev/null +++ b/test/CodeGen/AArch64/Redundantstore.ll @@ -0,0 +1,25 @@ +; RUN: llc -O3 -march=aarch64 < %s | FileCheck %s + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +@end_of_array = common global i8* null, align 8 + +; CHECK-LABEL: @test +; CHECK: stur +; CHECK-NOT: stur +define i8* @test(i32 %size) { +entry: + %0 = load i8** @end_of_array, align 8 + %conv = sext i32 %size to i64 + %and = and i64 %conv, -8 + %conv2 = trunc i64 %and to i32 + %add.ptr.sum = add nsw i64 %and, -4 + %add.ptr3 = getelementptr inbounds i8* %0, i64 %add.ptr.sum + %size4 = bitcast i8* %add.ptr3 to i32* + store i32 %conv2, i32* %size4, align 4 + %add.ptr.sum9 = add nsw i64 %and, -4 + %add.ptr5 = getelementptr inbounds i8* %0, i64 %add.ptr.sum9 + %size6 = bitcast i8* %add.ptr5 to i32* + store i32 %conv2, i32* %size6, align 4 + ret i8* %0 +} +