From ccfbbaca3fbd4957dc24a01cd6a9fd0dec4fbd88 Mon Sep 17 00:00:00 2001 From: Renato Golin Date: Tue, 9 Sep 2014 09:57:59 +0000 Subject: [PATCH] ARM: Negative offset support problem This patch is to permit a negative offset usage for a non frame access. Patch by Igor Oblakov. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217431 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/ARM/ARMISelDAGToDAG.cpp | 4 ++-- test/CodeGen/ARM/negative-offset.ll | 17 +++++++++++++++++ 2 files changed, 19 insertions(+), 2 deletions(-) create mode 100644 test/CodeGen/ARM/negative-offset.ll diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp index e547600624a..996bb1f0014 100644 --- a/lib/Target/ARM/ARMISelDAGToDAG.cpp +++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp @@ -542,11 +542,11 @@ bool ARMDAGToDAGISel::SelectAddrModeImm12(SDValue N, } if (ConstantSDNode *RHS = dyn_cast(N.getOperand(1))) { - int RHSC = (int)RHS->getZExtValue(); + int RHSC = (int)RHS->getSExtValue(); if (N.getOpcode() == ISD::SUB) RHSC = -RHSC; - if (RHSC >= 0 && RHSC < 0x1000) { // 12 bits (unsigned) + if (RHSC > -0x1000 && RHSC < 0x1000) { // 12 bits Base = N.getOperand(0); if (Base.getOpcode() == ISD::FrameIndex) { int FI = cast(Base)->getIndex(); diff --git a/test/CodeGen/ARM/negative-offset.ll b/test/CodeGen/ARM/negative-offset.ll new file mode 100644 index 00000000000..7b949fd71fe --- /dev/null +++ b/test/CodeGen/ARM/negative-offset.ll @@ -0,0 +1,17 @@ +; RUN: llc -mtriple=arm-eabi -O3 %s -o - | FileCheck %s + +; Function Attrs: nounwind readonly +define arm_aapcscc i32 @sum(i32* nocapture readonly %p) #0 { +entry: +;CHECK-LABEL: sum: +;CHECK-NOT: sub +;CHECK: ldr r{{.*}}, [r0, #-16] +;CHECK: ldr r{{.*}}, [r0, #-8] + %arrayidx = getelementptr inbounds i32* %p, i32 -4 + %0 = load i32* %arrayidx, align 4 + %arrayidx1 = getelementptr inbounds i32* %p, i32 -2 + %1 = load i32* %arrayidx1, align 4 + %add = add nsw i32 %1, %0 + ret i32 %add +} +