From 1a3f524e3c4da0393569f007ece81fe3ecb9352d Mon Sep 17 00:00:00 2001 From: Guozhi Wei Date: Thu, 15 Mar 2018 17:49:12 +0000 Subject: [PATCH] [PPC] Avoid non-simple MVT in STBRX optimization PR35402 triggered this case. It bswap and stores a 48bit value, current STBRX optimization transforms it into STBRX. Unfortunately 48bit is not a simple MVT, there is no PPC instruction to support it, and it can't be automatically expanded by llvm, so caused a crash. This patch detects the non-simple MVT and returns early. Differential Revision: https://reviews.llvm.org/D44500 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327651 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/PowerPC/PPCISelLowering.cpp | 6 +++++- test/CodeGen/PowerPC/pr35402.ll | 18 ++++++++++++++++++ 2 files changed, 23 insertions(+), 1 deletion(-) create mode 100644 test/CodeGen/PowerPC/pr35402.ll diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp index f9de65f..eeb1bf1 100644 --- a/lib/Target/PowerPC/PPCISelLowering.cpp +++ b/lib/Target/PowerPC/PPCISelLowering.cpp @@ -12221,6 +12221,11 @@ SDValue PPCTargetLowering::PerformDAGCombine(SDNode *N, N->getOperand(1).getValueType() == MVT::i16 || (Subtarget.hasLDBRX() && Subtarget.isPPC64() && N->getOperand(1).getValueType() == MVT::i64))) { + // STBRX can only handle simple types. + EVT mVT = cast(N)->getMemoryVT(); + if (mVT.isExtended()) + break; + SDValue BSwapOp = N->getOperand(1).getOperand(0); // Do an any-extend to 32-bits if this is a half-word input. if (BSwapOp.getValueType() == MVT::i16) @@ -12228,7 +12233,6 @@ SDValue PPCTargetLowering::PerformDAGCombine(SDNode *N, // If the type of BSWAP operand is wider than stored memory width // it need to be shifted to the right side before STBRX. - EVT mVT = cast(N)->getMemoryVT(); if (Op1VT.bitsGT(mVT)) { int Shift = Op1VT.getSizeInBits() - mVT.getSizeInBits(); BSwapOp = DAG.getNode(ISD::SRL, dl, Op1VT, BSwapOp, diff --git a/test/CodeGen/PowerPC/pr35402.ll b/test/CodeGen/PowerPC/pr35402.ll new file mode 100644 index 0000000..06e6d96 --- /dev/null +++ b/test/CodeGen/PowerPC/pr35402.ll @@ -0,0 +1,18 @@ +; RUN: llc -O2 < %s | FileCheck %s +target triple = "powerpc64le-linux-gnu" + +define void @test(i8* %p, i64 %data) { +entry: + %0 = tail call i64 @llvm.bswap.i64(i64 %data) + %ptr = bitcast i8* %p to i48* + %val = trunc i64 %0 to i48 + store i48 %val, i48* %ptr, align 1 + ret void + +; CHECK: sth +; CHECK: stw +; CHECK-NOT: stdbrx + +} + +declare i64 @llvm.bswap.i64(i64) -- 1.8.3.1