[llvm] r326226 - ARM: Don't rewrite add reg, $sp, 0 -> mov reg, $sp if the add defines CPSR.

[Peter Collingbourne via llvm-commits]

Author: pcc
Date: Tue Feb 27 11:00:59 2018
New Revision: 326226

URL: http://llvm.org/viewvc/llvm-project?rev=326226&view=rev
Log:
ARM: Don't rewrite add reg, $sp, 0 -> mov reg, $sp if the add defines CPSR.

Differential Revision: https://reviews.llvm.org/D43807

Added:
    llvm/trunk/test/CodeGen/Thumb2/cmp-frame.ll
Modified:
    llvm/trunk/lib/Target/ARM/Thumb2InstrInfo.cpp

Modified: llvm/trunk/lib/Target/ARM/Thumb2InstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Thumb2InstrInfo.cpp?rev=326226&r1=326225&r2=326226&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Thumb2InstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/ARM/Thumb2InstrInfo.cpp Tue Feb 27 11:00:59 2018
@@ -489,7 +489,8 @@ bool llvm::rewriteT2FrameIndex(MachineIn
     Offset += MI.getOperand(FrameRegIdx+1).getImm();
 
     unsigned PredReg;
-    if (Offset == 0 && getInstrPredicate(MI, PredReg) == ARMCC::AL) {
+    if (Offset == 0 && getInstrPredicate(MI, PredReg) == ARMCC::AL &&
+        !MI.definesRegister(ARM::CPSR)) {
       // Turn it into a move.
       MI.setDesc(TII.get(ARM::tMOVr));
       MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false);

Added: llvm/trunk/test/CodeGen/Thumb2/cmp-frame.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Thumb2/cmp-frame.ll?rev=326226&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Thumb2/cmp-frame.ll (added)
+++ llvm/trunk/test/CodeGen/Thumb2/cmp-frame.ll Tue Feb 27 11:00:59 2018
@@ -0,0 +1,11 @@
+; RUN: llc < %s | FileCheck %s
+
+target triple = "thumbv7-linux-androideabi"
+
+define i1 @f() {
+  %a = alloca i8*
+  ; CHECK: adds.w r0, sp, #0
+  ; CHECK: it ne
+  %cmp = icmp ne i8** %a, null
+  ret i1 %cmp
+}