[llvm-commits] [llvm] r123089 - in /llvm/trunk: lib/Transforms/Scalar/MemCpyOptimizer.cpp test/Transforms/MemCpyOpt/form-memset.ll
Chris Lattner
sabre at nondot.org
Sat Jan 8 13:19:19 PST 2011
Author: lattner
Date: Sat Jan 8 15:19:19 2011
New Revision: 123089
URL: http://llvm.org/viewvc/llvm-project?rev=123089&view=rev
Log:
Merge memsets followed by neighboring memsets and other stores into
larger memsets. Among other things, this fixes rdar://8760394 and
allows us to handle "Example 2" from http://blog.regehr.org/archives/320,
compiling it into a single 4096-byte memset:
_mad_synth_mute: ## @mad_synth_mute
## BB#0: ## %entry
pushq %rax
movl $4096, %esi ## imm = 0x1000
callq ___bzero
popq %rax
ret
Modified:
llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp
llvm/trunk/test/Transforms/MemCpyOpt/form-memset.ll
Modified: llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp?rev=123089&r1=123088&r2=123089&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp Sat Jan 8 15:19:19 2011
@@ -322,6 +322,7 @@
// Helper fuctions
bool processStore(StoreInst *SI, BasicBlock::iterator &BBI);
+ bool processMemSet(MemSetInst *SI, BasicBlock::iterator &BBI);
bool processMemCpy(MemCpyInst *M);
bool processMemMove(MemMoveInst *M);
bool performCallSlotOptzn(Instruction *cpy, Value *cpyDst, Value *cpySrc,
@@ -511,6 +512,17 @@
return false;
}
+bool MemCpyOpt::processMemSet(MemSetInst *MSI, BasicBlock::iterator &BBI) {
+ // See if there is another memset or store neighboring this memset which
+ // allows us to widen out the memset to do a single larger store.
+ if (Instruction *I = tryMergingIntoMemset(MSI, MSI->getDest(),
+ MSI->getValue())) {
+ BBI = I; // Don't invalidate iterator.
+ return true;
+ }
+ return false;
+}
+
/// performCallSlotOptzn - takes a memcpy and a call that it depends on,
/// and checks for the possibility of a call slot optimization by having
@@ -775,6 +787,7 @@
return true;
}
}
+
return false;
}
@@ -884,11 +897,13 @@
if (StoreInst *SI = dyn_cast<StoreInst>(I))
MadeChange |= processStore(SI, BI);
- else if (MemCpyInst *M = dyn_cast<MemCpyInst>(I)) {
+ else if (MemSetInst *M = dyn_cast<MemSetInst>(I))
+ RepeatInstruction = processMemSet(M, BI);
+ else if (MemCpyInst *M = dyn_cast<MemCpyInst>(I))
RepeatInstruction = processMemCpy(M);
- } else if (MemMoveInst *M = dyn_cast<MemMoveInst>(I)) {
+ else if (MemMoveInst *M = dyn_cast<MemMoveInst>(I))
RepeatInstruction = processMemMove(M);
- } else if (CallSite CS = (Value*)I) {
+ else if (CallSite CS = (Value*)I) {
for (unsigned i = 0, e = CS.arg_size(); i != e; ++i)
if (CS.paramHasAttr(i+1, Attribute::ByVal))
MadeChange |= processByValArgument(CS, i);
Modified: llvm/trunk/test/Transforms/MemCpyOpt/form-memset.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/MemCpyOpt/form-memset.ll?rev=123089&r1=123088&r2=123089&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/MemCpyOpt/form-memset.ll (original)
+++ llvm/trunk/test/Transforms/MemCpyOpt/form-memset.ll Sat Jan 8 15:19:19 2011
@@ -164,6 +164,7 @@
declare void @foo(%struct.MV*, %struct.MV*, i8*)
+; Store followed by memset.
define void @test3(i32* nocapture %P) nounwind ssp {
entry:
%arrayidx = getelementptr inbounds i32* %P, i64 1
@@ -177,6 +178,7 @@
; CHECK: call void @llvm.memset.p0i8.i64(i8* %1, i8 0, i64 15, i32 4, i1 false)
}
+; store followed by memset, different offset scenario
define void @test4(i32* nocapture %P) nounwind ssp {
entry:
store i32 0, i32* %P, align 4
@@ -191,4 +193,30 @@
declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) nounwind
+; Memset followed by store.
+define void @test5(i32* nocapture %P) nounwind ssp {
+entry:
+ %add.ptr = getelementptr inbounds i32* %P, i64 2
+ %0 = bitcast i32* %add.ptr to i8*
+ tail call void @llvm.memset.p0i8.i64(i8* %0, i8 0, i64 11, i32 1, i1 false)
+ %arrayidx = getelementptr inbounds i32* %P, i64 1
+ store i32 0, i32* %arrayidx, align 4
+ ret void
+; CHECK: @test5
+; CHECK-NOT: store
+; CHECK: call void @llvm.memset.p0i8.i64(i8* %1, i8 0, i64 15, i32 4, i1 false)
+}
+
+;; Memset followed by memset.
+define void @test6(i32* nocapture %P) nounwind ssp {
+entry:
+ %0 = bitcast i32* %P to i8*
+ tail call void @llvm.memset.p0i8.i64(i8* %0, i8 0, i64 12, i32 1, i1 false)
+ %add.ptr = getelementptr inbounds i32* %P, i64 3
+ %1 = bitcast i32* %add.ptr to i8*
+ tail call void @llvm.memset.p0i8.i64(i8* %1, i8 0, i64 12, i32 1, i1 false)
+ ret void
+; CHECK: @test6
+; CHECK: call void @llvm.memset.p0i8.i64(i8* %2, i8 0, i64 24, i32 1, i1 false)
+}
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