From 2f7fcd71982678879803b96574526f0a22b3918e Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Thu, 28 Apr 2011 23:03:25 +0000
Subject: [PATCH] Fix a rather obscure crash caused by ARM fast-isel generating
 code which redefines a register. rdar://problem/9338332 .

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130454 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMFastISel.cpp             | 21 ++-------------------
 test/CodeGen/ARM/fast-isel-redefinition.ll | 11 +++++++++++
 2 files changed, 13 insertions(+), 19 deletions(-)
 create mode 100644 test/CodeGen/ARM/fast-isel-redefinition.ll

diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 3e0b755ff84..54b9d2d1550 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -822,26 +822,9 @@ void ARMFastISel::ARMSimplifyAddress(Address &Addr, EVT VT) {
   // Since the offset is too large for the load/store instruction
   // get the reg+offset into a register.
   if (needsLowering) {
-    ARMCC::CondCodes Pred = ARMCC::AL;
-    unsigned PredReg = 0;
-
-    TargetRegisterClass *RC = isThumb ? ARM::tGPRRegisterClass :
-      ARM::GPRRegisterClass;
-    unsigned BaseReg = createResultReg(RC);
-
-    if (!isThumb)
-      emitARMRegPlusImmediate(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
-                              BaseReg, Addr.Base.Reg, Addr.Offset,
-                              Pred, PredReg,
-                              static_cast<const ARMBaseInstrInfo&>(TII));
-    else {
-      assert(AFI->isThumb2Function());
-      emitT2RegPlusImmediate(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
-                             BaseReg, Addr.Base.Reg, Addr.Offset, Pred, PredReg,
-                             static_cast<const ARMBaseInstrInfo&>(TII));
-    }
+    Addr.Base.Reg = FastEmit_ri_(MVT::i32, ISD::ADD, Addr.Base.Reg,
+                                 /*Op0IsKill*/false, Addr.Offset, MVT::i32);
     Addr.Offset = 0;
-    Addr.Base.Reg = BaseReg;
   }
 }
 
diff --git a/test/CodeGen/ARM/fast-isel-redefinition.ll b/test/CodeGen/ARM/fast-isel-redefinition.ll
new file mode 100644
index 00000000000..262432f807a
--- /dev/null
+++ b/test/CodeGen/ARM/fast-isel-redefinition.ll
@@ -0,0 +1,11 @@
+; RUN: llc -O0 -regalloc=linearscan | grep "ldr r0"
+; This isn't exactly a useful set of command-line options, but check that it
+; doesn't crash.  (It was crashing because a register was getting redefined.)
+
+target triple = "thumbv7-apple-macosx10.6.7"
+
+define i32 @f(i32* %x) nounwind ssp {
+  %y = getelementptr inbounds i32* %x, i32 5000
+  %tmp103 = load i32* %y, align 4
+  ret i32 %tmp103
+}