Enhance LICM to promote alias sets whose pointers themselves are stored,

which doesn't affect the memory address being promoted.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122172 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2010-12-19 05:57:25 +00:00
parent 1c0af0ed25
commit 1dec0d2704
2 changed files with 34 additions and 1 deletions

View File

@ -691,7 +691,10 @@ void LICM::PromoteAliasSet(AliasSet &AS) {
if (isa<LoadInst>(Use))
assert(!cast<LoadInst>(Use)->isVolatile() && "AST broken");
else if (isa<StoreInst>(Use)) {
if (Use->getOperand(0) == ASIV) return;
// Stores *of* the pointer are not interesting, only stores *to* the
// pointer.
if (Use->getOperand(1) != ASIV)
continue;
assert(!cast<StoreInst>(Use)->isVolatile() && "AST broken");
} else
return; // Not a load or store.

View File

@ -118,3 +118,33 @@ exit:
ret void
}
define void @test5(i32 %i, i32** noalias %P2) {
Entry:
br label %Loop
; CHECK: @test5
; CHECK: Entry:
; CHECK-NEXT: load i32* @X
; CHECK-NEXT: br label %Loop
Loop: ; preds = %Loop, %0
%j = phi i32 [ 0, %Entry ], [ %Next, %Loop ] ; <i32> [#uses=1]
%x = load i32* @X ; <i32> [#uses=1]
%x2 = add i32 %x, 1 ; <i32> [#uses=1]
store i32 %x2, i32* @X
volatile store i32* @X, i32** %P2
%Next = add i32 %j, 1 ; <i32> [#uses=2]
%cond = icmp eq i32 %Next, 0 ; <i1> [#uses=1]
br i1 %cond, label %Out, label %Loop
Out:
ret void
; CHECK: Out:
; CHECK-NEXT: store i32 %x2, i32* @X
; CHECK-NEXT: ret void
}