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[ArgPromotion] Check dereferenceability on argument as well 

Before walking all the callers, check whether we have a
dereferenceable attribute directly on the argument.

Also make it clearer that the code currently does not treat
alignment correctly.
This commit is contained in:
Nikita Popov 2022-02-08 10:29:51 +01:00
parent c2b476767e
commit b896334834
2 changed files with 13 additions and 11 deletions
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16
llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
View File

@ -477,18 +477,20 @@ doPromotion(Function *F, SmallPtrSetImpl<Argument *> &ArgsToPromote,
static bool allCallersPassValidPointerForArgument(Argument *Arg, Type *Ty) {
Function *Callee = Arg->getParent();
const DataLayout &DL = Callee->getParent()->getDataLayout();
Align NeededAlign(1); // TODO: This is incorrect!
APInt Bytes(64, DL.getTypeStoreSize(Ty));
unsigned ArgNo = Arg->getArgNo();
// Check if the argument itself is marked dereferenceable and aligned.
if (isDereferenceableAndAlignedPointer(Arg, NeededAlign, Bytes, DL))
return true;
// Look at all call sites of the function. At this point we know we only have
// direct callees.
for (User *U : Callee->users()) {
return all_of(Callee->users(), [&](User *U) {
CallBase &CB = cast<CallBase>(*U);
if (!isDereferenceablePointer(CB.getArgOperand(ArgNo), Ty, DL))
return false;
}
return true;
return isDereferenceableAndAlignedPointer(
CB.getArgOperand(Arg->getArgNo()), NeededAlign, Bytes, DL);
});
}
/// Returns true if Prefix is a prefix of longer. That means, Longer has a size

8
llvm/test/Transforms/ArgumentPromotion/align.ll
View File

@ -53,11 +53,10 @@ define void @caller_guaranteed_aligned_1(i1 %c, i32* align 16 dereferenceable(4)
define internal i32 @callee_guaranteed_aligned_2(i1 %c, i32* align 16 dereferenceable(4) %p) {
; CHECK-LABEL: define {{[^@]+}}@callee_guaranteed_aligned_2
; CHECK-SAME: (i1 [[C:%.*]], i32* align 16 dereferenceable(4) [[P:%.*]]) {
; CHECK-SAME: (i1 [[C:%.*]], i32 [[P_VAL:%.*]]) {
; CHECK-NEXT: br i1 [[C]], label [[IF:%.*]], label [[ELSE:%.*]]
; CHECK: if:
; CHECK-NEXT: [[X:%.*]] = load i32, i32* [[P]], align 16
; CHECK-NEXT: ret i32 [[X]]
; CHECK-NEXT: ret i32 [[P_VAL]]
; CHECK: else:
; CHECK-NEXT: ret i32 -1
;
@ -74,7 +73,8 @@ else:
define void @caller_guaranteed_aligned_2(i1 %c, i32* %p) {
; CHECK-LABEL: define {{[^@]+}}@caller_guaranteed_aligned_2
; CHECK-SAME: (i1 [[C:%.*]], i32* [[P:%.*]]) {
; CHECK-NEXT: [[TMP1:%.*]] = call i32 @callee_guaranteed_aligned_2(i1 [[C]], i32* [[P]])
; CHECK-NEXT: [[P_VAL:%.*]] = load i32, i32* [[P]], align 16
; CHECK-NEXT: [[TMP1:%.*]] = call i32 @callee_guaranteed_aligned_2(i1 [[C]], i32 [[P_VAL]])
; CHECK-NEXT: ret void
;
call i32 @callee_guaranteed_aligned_2(i1 %c, i32* %p)