[PATCH] D24854: [SROA] Drop lifetime.start/end intrinsics when they block promotion.
Eli Friedman via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 28 14:00:45 PST 2016
This revision was automatically updated to reflect the committed changes.
Closed by commit rL288074: [SROA] Drop lifetime.start/end intrinsics when they block promotion. (authored by efriedma).
Changed prior to commit:
https://reviews.llvm.org/D24854?vs=74556&id=79454#toc
Repository:
rL LLVM
https://reviews.llvm.org/D24854
Files:
llvm/trunk/lib/Transforms/Scalar/SROA.cpp
llvm/trunk/test/Transforms/SROA/basictest.ll
Index: llvm/trunk/test/Transforms/SROA/basictest.ll
===================================================================
--- llvm/trunk/test/Transforms/SROA/basictest.ll
+++ llvm/trunk/test/Transforms/SROA/basictest.ll
@@ -1672,9 +1672,8 @@
define void @PR27999() unnamed_addr {
; CHECK-LABEL: @PR27999(
-; CHECK: alloca [2 x i64], align 8
-; CHECK: call void @llvm.lifetime.start(i64 16,
-; CHECK: call void @llvm.lifetime.end(i64 8,
+; CHECK: entry-block:
+; CHECK-NEXT: ret void
entry-block:
%0 = alloca [2 x i64], align 8
%1 = bitcast [2 x i64]* %0 to i8*
@@ -1684,3 +1683,15 @@
call void @llvm.lifetime.end(i64 8, i8* %3)
ret void
}
+
+define void @PR29139() {
+; CHECK-LABEL: @PR29139(
+; CHECK: bb1:
+; CHECK-NEXT: ret void
+bb1:
+ %e.7.sroa.6.i = alloca i32, align 1
+ %e.7.sroa.6.0.load81.i = load i32, i32* %e.7.sroa.6.i, align 1
+ %0 = bitcast i32* %e.7.sroa.6.i to i8*
+ call void @llvm.lifetime.end(i64 2, i8* %0)
+ ret void
+}
Index: llvm/trunk/lib/Transforms/Scalar/SROA.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Scalar/SROA.cpp
+++ llvm/trunk/lib/Transforms/Scalar/SROA.cpp
@@ -2876,6 +2876,17 @@
// Record this instruction for deletion.
Pass.DeadInsts.insert(&II);
+ // Lifetime intrinsics are only promotable if they cover the whole alloca.
+ // Therefore, we drop lifetime intrinsics which don't cover the whole
+ // alloca.
+ // (In theory, intrinsics which partially cover an alloca could be
+ // promoted, but PromoteMemToReg doesn't handle that case.)
+ // FIXME: Check whether the alloca is promotable before dropping the
+ // lifetime intrinsics?
+ if (NewBeginOffset != NewAllocaBeginOffset ||
+ NewEndOffset != NewAllocaEndOffset)
+ return true;
+
ConstantInt *Size =
ConstantInt::get(cast<IntegerType>(II.getArgOperand(0)->getType()),
NewEndOffset - NewBeginOffset);
@@ -2889,12 +2900,7 @@
(void)New;
DEBUG(dbgs() << " to: " << *New << "\n");
- // Lifetime intrinsics are only promotable if they cover the whole alloca.
- // (In theory, intrinsics which partially cover an alloca could be
- // promoted, but PromoteMemToReg doesn't handle that case.)
- bool IsWholeAlloca = NewBeginOffset == NewAllocaBeginOffset &&
- NewEndOffset == NewAllocaEndOffset;
- return IsWholeAlloca;
+ return true;
}
bool visitPHINode(PHINode &PN) {
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