diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h index 8beabc7b03e..3c7dc885ba8 100644 --- a/include/llvm/Target/TargetLowering.h +++ b/include/llvm/Target/TargetLowering.h @@ -1153,6 +1153,12 @@ public: return false; } + /// Returns true if a cast from SrcAS to DestAS is "cheap", such that e.g. we + /// are happy to sink it into basic blocks. + virtual bool isCheapAddrSpaceCast(unsigned SrcAS, unsigned DestAS) const { + return isNoopAddrSpaceCast(SrcAS, DestAS); + } + /// Return true if the pointer arguments to CI should be aligned by aligning /// the object whose address is being passed. If so then MinSize is set to the /// minimum size the object must be to be aligned and PrefAlign is set to the diff --git a/lib/CodeGen/CodeGenPrepare.cpp b/lib/CodeGen/CodeGenPrepare.cpp index 87ad3075873..68f090ccee2 100644 --- a/lib/CodeGen/CodeGenPrepare.cpp +++ b/lib/CodeGen/CodeGenPrepare.cpp @@ -927,6 +927,14 @@ static bool SinkCast(CastInst *CI) { /// static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI, const DataLayout &DL) { + // Sink only "cheap" (or nop) address-space casts. This is a weaker condition + // than sinking only nop casts, but is helpful on some platforms. + if (auto *ASC = dyn_cast(CI)) { + if (!TLI.isCheapAddrSpaceCast(ASC->getSrcAddressSpace(), + ASC->getDestAddressSpace())) + return false; + } + // If this is a noop copy, EVT SrcVT = TLI.getValueType(DL, CI->getOperand(0)->getType()); EVT DstVT = TLI.getValueType(DL, CI->getType()); diff --git a/test/Transforms/CodeGenPrepare/NVPTX/dont-sink-nop-addrspacecast.ll b/test/Transforms/CodeGenPrepare/NVPTX/dont-sink-nop-addrspacecast.ll new file mode 100644 index 00000000000..97b24906d16 --- /dev/null +++ b/test/Transforms/CodeGenPrepare/NVPTX/dont-sink-nop-addrspacecast.ll @@ -0,0 +1,21 @@ +; RUN: opt -S -codegenprepare < %s | FileCheck %s + +target datalayout = "e-i64:64-v16:16-v32:32-n16:32:64" +target triple = "nvptx64-nvidia-cuda" + +; CHECK-LABEL: @test +define i64 @test(i1 %pred, i64* %ptr) { +; CHECK: addrspacecast + %ptr_as1 = addrspacecast i64* %ptr to i64 addrspace(1)* + br i1 %pred, label %l1, label %l2 +l1: +; CHECK-LABEL: l1: +; CHECK-NOT: addrspacecast + %v1 = load i64, i64* %ptr + ret i64 %v1 +l2: + ; CHECK-LABEL: l2: + ; CHECK-NOT: addrspacecast + %v2 = load i64, i64 addrspace(1)* %ptr_as1 + ret i64 %v2 +}