[llvm] r331549 - [MachineLICM] Debug intrinsics shouldn't affect hoist decisions
Geoff Berry via llvm-commits
llvm-commits at lists.llvm.org
Fri May 4 12:25:09 PDT 2018
Author: gberry
Date: Fri May 4 12:25:09 2018
New Revision: 331549
URL: http://llvm.org/viewvc/llvm-project?rev=331549&view=rev
Log:
[MachineLICM] Debug intrinsics shouldn't affect hoist decisions
Summary:
When checking if an instruction stores to a given frame index, check
that the instruction can write to memory before looking at the memory
operands list to avoid e.g. DBG_VALUE instructions that reference a
frame index preventing a load from that index from being hoisted.
Reviewers: dblaikie, MatzeB, qcolombet, reames, javed.absar
Subscribers: mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D46284
Added:
llvm/trunk/test/CodeGen/AArch64/mlicm-stack-write-check.mir
Modified:
llvm/trunk/lib/CodeGen/MachineLICM.cpp
Modified: llvm/trunk/lib/CodeGen/MachineLICM.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineLICM.cpp?rev=331549&r1=331548&r2=331549&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineLICM.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineLICM.cpp Fri May 4 12:25:09 2018
@@ -374,6 +374,10 @@ bool MachineLICMBase::runOnMachineFuncti
/// Return true if instruction stores to the specified frame.
static bool InstructionStoresToFI(const MachineInstr *MI, int FI) {
+ // Check mayStore before memory operands so that e.g. DBG_VALUEs will return
+ // true since they have no memory operands.
+ if (!MI->mayStore())
+ return false;
// If we lost memory operands, conservatively assume that the instruction
// writes to all slots.
if (MI->memoperands_empty())
Added: llvm/trunk/test/CodeGen/AArch64/mlicm-stack-write-check.mir
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/mlicm-stack-write-check.mir?rev=331549&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/mlicm-stack-write-check.mir (added)
+++ llvm/trunk/test/CodeGen/AArch64/mlicm-stack-write-check.mir Fri May 4 12:25:09 2018
@@ -0,0 +1,32 @@
+# RUN: llc -mtriple=aarch64 -run-pass machinelicm -verify-machineinstrs -o - %s | FileCheck %s
+---
+name: test
+tracksRegLiveness: true
+registers:
+ - { id: 0, class: gpr64 }
+stack:
+ - { id: 0, size: 8, type: spill-slot }
+body: |
+ bb.0:
+ ; CHECK-LABEL: name: test
+ ; CHECK-LABEL: bb.0:
+ ; CHECK: $x2 = LDRXui %stack.0, 0
+ liveins: $x0, $x1, $x2
+ B %bb.1
+
+ bb.1:
+ ; CHECK-LABEL: bb.1:
+ ; CHECK-NOT: $x2 = LDRXui %stack.0, 0
+ liveins: $x0
+ DBG_VALUE %stack.0, 0
+ $x2 = LDRXui %stack.0, 0 :: (load 8 from %stack.0)
+ $x0 = ADDXrr $x0, $x2
+ $xzr = SUBSXri $x0, 1, 0, implicit-def $nzcv
+ Bcc 11, %bb.1, implicit $nzcv
+ B %bb.2
+
+ bb.2:
+ liveins: $x0
+ %0 = COPY $x0
+ %0 = COPY $x0 ; Force isSSA = false.
+...
More information about the llvm-commits
mailing list