Don't kill the base register when expanding strd.

When an strd instruction doesn't get the registers it wants, it can be
expanded into two str instructions. Make sure the first str doesn't kill
the base register in the case where the base and data registers are
identical:

  t2STRi12 %R0<kill>, %R0, 4, pred:14, pred:%noreg
  t2STRi12 %R2<kill>, %R0, 8, pred:14, pred:%noreg

<rdar://problem/11101911>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153611 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/ARMLoadStoreOptimizer.cpp b/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
index f75ac90b22ea2d9b934faca14604e2df0315fce2..5770f7739ae6d7d731e4bd7d9c61a58aac8acdc0 100644 (file)
--- a/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
+++ b/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
@@ -1184,6 +1184,10 @@ bool ARMLoadStoreOpt::FixInvalidRegPairOp(MachineBasicBlock &MBB,
           EvenDeadKill = false;
           OddDeadKill = true;
         }
+        // Never kill the base register in the first instruction.
+        // <rdar://problem/11101911>
+        if (EvenReg == BaseReg)
+          EvenDeadKill = false;
         InsertLDR_STR(MBB, MBBI, OffImm, isLd, dl, NewOpc,
                       EvenReg, EvenDeadKill, EvenUndef,
                       BaseReg, false, BaseUndef, false, OffUndef,

diff --git a/test/CodeGen/Thumb2/crash.ll b/test/CodeGen/Thumb2/crash.ll
index 52893af9370efde9e95bc5dd4733991fa859e832..cb4d08058f41068e6944ec0ebf0a65800fa777c0 100644 (file)
--- a/test/CodeGen/Thumb2/crash.ll
+++ b/test/CodeGen/Thumb2/crash.ll
@@ -61,3 +61,18 @@ entry:
 declare <4 x float> @llvm.arm.neon.vld1.v4f32(i8*, i32) nounwind readonly
 
 declare void @llvm.arm.neon.vst1.v4f32(i8*, <4 x float>, i32) nounwind
+
+; <rdar://problem/11101911>
+; When an strd is expanded into two str instructions, make sure the first str
+; doesn't kill the base register. This can happen if the base register is the
+; same as the data register.
+%class = type { i8*, %class*, i32 }
+define void @f11101911(%class* %this, i32 %num) ssp align 2 {
+entry:
+  %p1 = getelementptr inbounds %class* %this, i32 0, i32 1
+  %p2 = getelementptr inbounds %class* %this, i32 0, i32 2
+  tail call void asm sideeffect "", "~{r1},~{r3},~{r5},~{r11},~{r13}"() nounwind
+  store %class* %this, %class** %p1, align 4
+  store i32 %num, i32* %p2, align 4
+  ret void
+}