[llvm] r350289 - [CodeGen] Skip over dbg-instr in twoaddr pass
Markus Lavin via llvm-commits
llvm-commits at lists.llvm.org
Thu Jan 3 00:36:07 PST 2019
Author: markus
Date: Thu Jan 3 00:36:06 2019
New Revision: 350289
URL: http://llvm.org/viewvc/llvm-project?rev=350289&view=rev
Log:
[CodeGen] Skip over dbg-instr in twoaddr pass
A DBG_VALUE between a two-address instruction and a following COPY
would prevent rescheduleMIBelowKill optimization inside
TwoAddressInstructionPass.
Differential Revision: https://reviews.llvm.org/D55987
Added:
llvm/trunk/test/CodeGen/X86/twoaddr-dbg-value.mir
Modified:
llvm/trunk/lib/CodeGen/TwoAddressInstructionPass.cpp
Modified: llvm/trunk/lib/CodeGen/TwoAddressInstructionPass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TwoAddressInstructionPass.cpp?rev=350289&r1=350288&r2=350289&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TwoAddressInstructionPass.cpp (original)
+++ llvm/trunk/lib/CodeGen/TwoAddressInstructionPass.cpp Thu Jan 3 00:36:06 2019
@@ -929,9 +929,12 @@ rescheduleMIBelowKill(MachineBasicBlock:
MachineBasicBlock::iterator Begin = MI;
MachineBasicBlock::iterator AfterMI = std::next(Begin);
MachineBasicBlock::iterator End = AfterMI;
- while (End->isCopy() &&
- regOverlapsSet(Defs, End->getOperand(1).getReg(), TRI)) {
- Defs.push_back(End->getOperand(0).getReg());
+ while (End != MBB->end()) {
+ End = skipDebugInstructionsForward(End, MBB->end());
+ if (End->isCopy() && regOverlapsSet(Defs, End->getOperand(1).getReg(), TRI))
+ Defs.push_back(End->getOperand(0).getReg());
+ else
+ break;
++End;
}
Added: llvm/trunk/test/CodeGen/X86/twoaddr-dbg-value.mir
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/twoaddr-dbg-value.mir?rev=350289&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/twoaddr-dbg-value.mir (added)
+++ llvm/trunk/test/CodeGen/X86/twoaddr-dbg-value.mir Thu Jan 3 00:36:06 2019
@@ -0,0 +1,27 @@
+# RUN: llc -run-pass=livevars,twoaddressinstruction -mtriple=x86_64-- -o - %s | FileCheck %s
+---
+name: foo
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $edi
+
+ %0:gr32 = COPY killed $edi
+ %1:gr32 = COPY killed %0
+ %4:gr32 = XOR32ri8 %1, 1, implicit-def dead $eflags
+ DBG_VALUE %4
+ %5:gr32 = COPY %4
+ PUSH32r killed %1, implicit-def $esp, implicit $esp
+ $eax = COPY killed %5
+ RETQ implicit killed $eax
+
+...
+
+# Verify that the DBG_VALUE instruction does not inhibit
+# TwoAddressInstructionPass::rescheduleMIBelowKill optimization
+
+# CHECK: PUSH32r %1, implicit-def $esp, implicit $esp
+# CHECK-NEXT: %2:gr32 = COPY killed %1
+# CHECK-NEXT: %2:gr32 = XOR32ri8 %2, 1, implicit-def dead $eflags
+# CHECK-NEXT: DBG_VALUE %2
+# CHECK-NEXT: %3:gr32 = COPY killed %2
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