[llvm] r367540 - [AArch64] Do not allocate unnecessary emergency slot.
Sander de Smalen via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 1 03:53:46 PDT 2019
Author: s.desmalen
Date: Thu Aug 1 03:53:45 2019
New Revision: 367540
URL: http://llvm.org/viewvc/llvm-project?rev=367540&view=rev
Log:
[AArch64] Do not allocate unnecessary emergency slot.
Fix an issue where the compiler still allocates an emergency spill slot even
though it already decided to spill an extra callee-save register to use
as a scratch register.
Reviewers: gberry, thegameg, mstorsjo, t.p.northover
Reviewed By: thegameg
Differential Revision: https://reviews.llvm.org/D65504
Added:
llvm/trunk/test/CodeGen/AArch64/extra-callee-save.mir
Modified:
llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp
Modified: llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp?rev=367540&r1=367539&r2=367540&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64FrameLowering.cpp Thu Aug 1 03:53:45 2019
@@ -2113,7 +2113,7 @@ void AArch64FrameLowering::determineCall
SavedRegs.set(AArch64::LR);
}
- LLVM_DEBUG(dbgs() << "*** determineCalleeSaves\nUsed CSRs:";
+ LLVM_DEBUG(dbgs() << "*** determineCalleeSaves\nSaved CSRs:";
for (unsigned Reg
: SavedRegs.set_bits()) dbgs()
<< ' ' << printReg(Reg, RegInfo);
@@ -2145,7 +2145,7 @@ void AArch64FrameLowering::determineCall
// store the pair.
if (produceCompactUnwindFrame(MF))
SavedRegs.set(UnspilledCSGPRPaired);
- ExtraCSSpill = UnspilledCSGPRPaired;
+ ExtraCSSpill = UnspilledCSGPR;
}
// If we didn't find an extra callee-saved register to spill, create
Added: llvm/trunk/test/CodeGen/AArch64/extra-callee-save.mir
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/extra-callee-save.mir?rev=367540&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/extra-callee-save.mir (added)
+++ llvm/trunk/test/CodeGen/AArch64/extra-callee-save.mir Thu Aug 1 03:53:45 2019
@@ -0,0 +1,28 @@
+#RUN: llc -mtriple=aarch64-- -run-pass prologepilog %s -o - | FileCheck %s
+# Check that we spill a scratch register, but not also an additional
+# emergency spill slot.
+---
+name: big_stack
+# CHECK-LABEL: name: big_stack
+# CHECK: frame-setup STPXi killed $x20, killed $x19
+# CHECK: $sp = frame-setup SUBXri $sp, 8, 12
+# CHECK-NOT: frame-setup SUBXri $sp, 16, 0
+tracksRegLiveness: true
+stack:
+ - { id: 0, name: '', size: 32761, alignment: 8 }
+body: |
+ bb.0:
+ $x19 = IMPLICIT_DEF
+ ; $x20 can be used as scratch register.
+ $x21 = IMPLICIT_DEF
+ $x22 = IMPLICIT_DEF
+ $x23 = IMPLICIT_DEF
+ $x24 = IMPLICIT_DEF
+ $x25 = IMPLICIT_DEF
+ $x26 = IMPLICIT_DEF
+ $x27 = IMPLICIT_DEF
+ $x28 = IMPLICIT_DEF
+ $lr = IMPLICIT_DEF
+ $fp = IMPLICIT_DEF
+ RET_ReallyLR
+...
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