ARM: fix folding stack adjustment (again again again...)

This time, the issue is that we weren't accounting for the possibility that
aligned DPRs could have been stored after the final "push" in a prologue. When
that happened we effectively moved a "sub sp, #N" from below the aligned stores
to above them, and everything went to pot.

To make it worse, I'd actually committed something testing that we produced
wrong code, so the test update is tiny.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248437 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/ARMFrameLowering.cpp b/lib/Target/ARM/ARMFrameLowering.cpp
index b52ca93c20452afdadae4b0b638d45f0a2b252fb..5b5b1b022f597df3da1b51ea328838f47e64be1d 100644 (file)
--- a/lib/Target/ARM/ARMFrameLowering.cpp
+++ b/lib/Target/ARM/ARMFrameLowering.cpp
@@ -488,7 +488,8 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF,
 
   if (NumBytes) {
     // Adjust SP after all the callee-save spills.
-    if (tryFoldSPUpdateIntoPushPop(STI, MF, LastPush, NumBytes))
+    if (AFI->getNumAlignedDPRCS2Regs() == 0 &&
+        tryFoldSPUpdateIntoPushPop(STI, MF, LastPush, NumBytes))
       DefCFAOffsetCandidates.addExtraBytes(LastPush, NumBytes);
     else {
       emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes,

diff --git a/test/CodeGen/ARM/fold-stack-adjust.ll b/test/CodeGen/ARM/fold-stack-adjust.ll
index 614966d402478d8b4fbf28192a0f1532cb5247e4..5bec6445560f223b7604a221f83f0f95316b9bfc 100644 (file)
--- a/test/CodeGen/ARM/fold-stack-adjust.ll
+++ b/test/CodeGen/ARM/fold-stack-adjust.ll
@@ -67,11 +67,12 @@ define void @check_vfp_fold() minsize {
   ; iOS uses aligned NEON stores here, which is convenient since we
   ; want to make sure that works too.
 ; CHECK-IOS-LABEL: check_vfp_fold:
-; CHECK-IOS: push {r0, r1, r2, r3, r4, r7, lr}
+; CHECK-IOS: push {r4, r7, lr}
 ; CHECK-IOS: sub.w r4, sp, #16
 ; CHECK-IOS: bfc r4, #0, #4
 ; CHECK-IOS: mov sp, r4
 ; CHECK-IOS: vst1.64 {d8, d9}, [r4:128]
+; CHECK-IOS: sub sp, #16
 ; ...
 ; CHECK-IOS: add r4, sp, #16
 ; CHECK-IOS: vld1.64 {d8, d9}, [r4:128]