[llvm] r307628 - [CGP] Relax a bit restriction for optimizeMemoryInst to extend scope
Serguei Katkov via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 10 23:24:44 PDT 2017
Author: skatkov
Date: Mon Jul 10 23:24:44 2017
New Revision: 307628
URL: http://llvm.org/viewvc/llvm-project?rev=307628&view=rev
Log:
[CGP] Relax a bit restriction for optimizeMemoryInst to extend scope
CodeGenPrepare::optimizeMemoryInst contains a check that we do nothing
if all instructions combining the address for memory instruction is in the same
block as memory instruction itself.
However if any of these instruction are placed after memory instruction then
address calculation will not be folded to memory instruction.
The added test case shows an example.
Reviewers: loladiro, spatel, efriedma
Reviewed By: efriedma
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D34862
Added:
llvm/trunk/test/CodeGen/X86/sink-gep-before-mem-inst.ll
Modified:
llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
Modified: llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp?rev=307628&r1=307627&r2=307628&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp (original)
+++ llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp Mon Jul 10 23:24:44 2017
@@ -4270,6 +4270,7 @@ bool CodeGenPrepare::optimizeMemoryInst(
Value *Consensus = nullptr;
unsigned NumUsesConsensus = 0;
bool IsNumUsesConsensusValid = false;
+ bool PhiSeen = false;
SmallVector<Instruction*, 16> AddrModeInsts;
ExtAddrMode AddrMode;
TypePromotionTransaction TPT(RemovedInsts);
@@ -4289,6 +4290,7 @@ bool CodeGenPrepare::optimizeMemoryInst(
if (PHINode *P = dyn_cast<PHINode>(V)) {
for (Value *IncValue : P->incoming_values())
worklist.push_back(IncValue);
+ PhiSeen = true;
continue;
}
@@ -4342,9 +4344,10 @@ bool CodeGenPrepare::optimizeMemoryInst(
TPT.commit();
// If all the instructions matched are already in this BB, don't do anything.
- if (none_of(AddrModeInsts, [&](Value *V) {
+ // If we saw Phi node then it is not local definitely.
+ if (!PhiSeen && none_of(AddrModeInsts, [&](Value *V) {
return IsNonLocalValue(V, MemoryInst->getParent());
- })) {
+ })) {
DEBUG(dbgs() << "CGP: Found local addrmode: " << AddrMode << "\n");
return false;
}
Added: llvm/trunk/test/CodeGen/X86/sink-gep-before-mem-inst.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/sink-gep-before-mem-inst.ll?rev=307628&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/sink-gep-before-mem-inst.ll (added)
+++ llvm/trunk/test/CodeGen/X86/sink-gep-before-mem-inst.ll Mon Jul 10 23:24:44 2017
@@ -0,0 +1,25 @@
+; RUN: opt < %s -S -codegenprepare -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
+
+define i64 @test.after(i8 addrspace(1)* readonly align 8) {
+; CHECK-LABEL: test.after
+; CHECK: sunkaddr
+entry:
+ %.0 = getelementptr inbounds i8, i8 addrspace(1)* %0, i64 8
+ %addr = bitcast i8 addrspace(1)* %.0 to i32 addrspace(1)*
+ br label %header
+
+header:
+ %addr.in.loop = phi i32 addrspace(1)* [ %addr, %entry ], [ %addr.after, %header ]
+ %local_2_ = phi i64 [ 0, %entry ], [ %.9, %header ]
+ %.7 = load i32, i32 addrspace(1)* %addr.in.loop, align 8
+ fence acquire
+ %.1 = getelementptr inbounds i8, i8 addrspace(1)* %0, i64 8
+ %addr.after = bitcast i8 addrspace(1)* %.1 to i32 addrspace(1)*
+ %.8 = sext i32 %.7 to i64
+ %.9 = add i64 %local_2_, %.8
+ %not. = icmp sgt i64 %.9, 999
+ br i1 %not., label %exit, label %header
+
+exit:
+ ret i64 %.9
+}
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