[llvm] r217498 - ARM: don't size-reduce STMs using the LR register.

[Tim Northover]

Author: tnorthover
Date: Wed Sep 10 07:53:28 2014
New Revision: 217498

URL: http://llvm.org/viewvc/llvm-project?rev=217498&view=rev
Log:
ARM: don't size-reduce STMs using the LR register.

The only Thumb-1 multi-store capable of using LR is the PUSH instruction, which
translates to STMDB, so we shouldn't convert STMIAs.

Patch by Sergey Dmitrouk.

Added:
    llvm/trunk/test/CodeGen/ARM/wrong-t2stmia-size-opt.ll
Modified:
    llvm/trunk/lib/Target/ARM/Thumb2SizeReduction.cpp

Modified: llvm/trunk/lib/Target/ARM/Thumb2SizeReduction.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Thumb2SizeReduction.cpp?rev=217498&r1=217497&r2=217498&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Thumb2SizeReduction.cpp (original)
+++ llvm/trunk/lib/Target/ARM/Thumb2SizeReduction.cpp Wed Sep 10 07:53:28 2014
@@ -335,7 +335,7 @@ static bool VerifyLowRegs(MachineInstr *
   bool isPCOk = (Opc == ARM::t2LDMIA_RET || Opc == ARM::t2LDMIA     ||
                  Opc == ARM::t2LDMDB     || Opc == ARM::t2LDMIA_UPD ||
                  Opc == ARM::t2LDMDB_UPD);
-  bool isLROk = (Opc == ARM::t2STMIA_UPD || Opc == ARM::t2STMDB_UPD);
+  bool isLROk = (Opc == ARM::t2STMDB_UPD);
   bool isSPOk = isPCOk || isLROk;
   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
     const MachineOperand &MO = MI->getOperand(i);

Added: llvm/trunk/test/CodeGen/ARM/wrong-t2stmia-size-opt.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/wrong-t2stmia-size-opt.ll?rev=217498&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/wrong-t2stmia-size-opt.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/wrong-t2stmia-size-opt.ll Wed Sep 10 07:53:28 2014
@@ -0,0 +1,20 @@
+; RUN: llc -mcpu=cortex-a9 -O1 -filetype=obj %s -o - | llvm-objdump -arch thumb -mcpu=cortex-a9 -d - | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i1:8:32-i8:8:32-i16:16:32-i64:64-v128:64:128-a:0:32-n32-S64"
+target triple = "thumbv7--linux-gnueabi"
+
+declare i8* @llvm.returnaddress(i32)
+
+define i32* @wrong-t2stmia-size-reduction(i32* %addr, i32 %val0) minsize {
+  store i32 %val0, i32* %addr
+  %addr1 = getelementptr i32* %addr, i32 1
+  %lr = call i8* @llvm.returnaddress(i32 0)
+  %lr32 = ptrtoint i8* %lr to i32
+  store i32 %lr32, i32* %addr1
+  %addr2 = getelementptr i32* %addr1, i32 1
+  ret i32* %addr2
+}
+
+; Check that stm writes two registers.  The bug caused one of registers (LR,
+; which invalid for Thumb1 form of STMIA instruction) to be dropped.
+; CHECK: stm{{[^,]*}}, {{{.*,.*}}}