[AArch64] Fix issues with large arrays on stack

Summary:
This patch fixes a few issues when large arrays are allocated on the
stack. Currently, clang has inconsistent behaviour, for debug builds
there is an assertion failure when the array size on stack is around 2GB
but there is no assertion when the stack is around 8GB. For release
builds there is no assertion, the compilation succeeds but generates
incorrect code. The incorrect code generated is due to using
int/unsigned int instead of their 64-bit counterparts. This patch,
1) Removes the assertion in frame legality check.
2) Converts int/unsigned int in some places to the 64-bit variants. This
helps in generating correct code and removes the inconsistent behaviour.
3) Adds a test which runs without optimisations.

Reviewers: sdesmalen, efriedma, fhahn, aemerson

Reviewed By: efriedma

Subscribers: eli.friedman, fpetrogalli, kristof.beyls, hiraditya,
llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70496

1 files changed, 4 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/MachineFrameInfo.cpp b/llvm/lib/CodeGen/MachineFrameInfo.cpp
index 604f514..22ab2c7 100644
--- a/llvm/lib/CodeGen/MachineFrameInfo.cpp
+++ b/llvm/lib/CodeGen/MachineFrameInfo.cpp
@@ -133,11 +133,11 @@ BitVector MachineFrameInfo::getPristineRegs(const MachineFunction &MF) const {
   return BV;
 }
 
-unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
+uint64_t MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
   const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering();
   const TargetRegisterInfo *RegInfo = MF.getSubtarget().getRegisterInfo();
   unsigned MaxAlign = getMaxAlignment();
-  int Offset = 0;
+  int64_t Offset = 0;
 
   // This code is very, very similar to PEI::calculateFrameObjectOffsets().
   // It really should be refactored to share code. Until then, changes
@@ -147,7 +147,7 @@ unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
     // Only estimate stack size of default stack.
     if (getStackID(i) != TargetStackID::Default)
       continue;
-    int FixedOff = -getObjectOffset(i);
+    int64_t FixedOff = -getObjectOffset(i);
     if (FixedOff > Offset) Offset = FixedOff;
   }
   for (unsigned i = 0, e = getObjectIndexEnd(); i != e; ++i) {
@@ -183,7 +183,7 @@ unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
   unsigned AlignMask = StackAlign - 1;
   Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
 
-  return (unsigned)Offset;
+  return (uint64_t)Offset;
 }
 
 void MachineFrameInfo::computeMaxCallFrameSize(const MachineFunction &MF) {