scavenged frame index value re-use gets confused when more than one base

register is involved for thumb1. Work around this for the moment by only
re-using SP-relative offsets. This is temporary 'til the code can distinguish
multiple base registers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98071 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 8 insertions, 1 deletions

diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index 577c36318f..8f35c37b9a 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -40,7 +40,7 @@
 #include "llvm/Support/CommandLine.h"
 using namespace llvm;
 
-static cl::opt<bool>
+cl::opt<bool>
 ReuseFrameIndexVals("arm-reuse-frame-index-vals", cl::Hidden, cl::init(true),
           cl::desc("Reuse repeated frame index values"));
 
diff --git a/lib/Target/ARM/Thumb1RegisterInfo.cpp b/lib/Target/ARM/Thumb1RegisterInfo.cpp
index 163d1e9a0d..7731802de4 100644
--- a/lib/Target/ARM/Thumb1RegisterInfo.cpp
+++ b/lib/Target/ARM/Thumb1RegisterInfo.cpp
@@ -33,10 +33,13 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
+extern cl::opt<bool> ReuseFrameIndexVals;
+
 Thumb1RegisterInfo::Thumb1RegisterInfo(const ARMBaseInstrInfo &tii,
                                        const ARMSubtarget &sti)
   : ARMBaseRegisterInfo(tii, sti) {
@@ -640,6 +643,7 @@ Thumb1RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
       assert (Value && "Frame index virtual allocated, but Value arg is NULL!");
       *Value = Offset;
       bool UseRR = false;
+      bool TrackVReg = FrameReg == ARM::SP;
 
       if (Opcode == ARM::tSpill) {
         if (FrameReg == ARM::SP)
@@ -648,6 +652,7 @@ Thumb1RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
         else {
           emitLoadConstPool(MBB, II, dl, VReg, 0, Offset);
           UseRR = true;
+          TrackVReg = false;
         }
       } else
         emitThumbRegPlusImmediate(MBB, II, VReg, FrameReg, Offset, TII,
@@ -658,6 +663,8 @@ Thumb1RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
         MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
       else // tSTR has an extra register operand.
         MI.addOperand(MachineOperand::CreateReg(0, false));
+      if (!ReuseFrameIndexVals || !TrackVReg)
+        VReg = 0;
   } else
     assert(false && "Unexpected opcode!");