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[ArgPromotion] Consider InvokeInst in Caller alias analysis (#110335)
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Check that all users of a Function are CallBase rather than CallInst
when performing alias analysis using actual arguments in the calling
function, as this check is also valid for Invoke instructions.

This allows replacing the existing check with an assert, as the Function
only being used by CallBase derived instructions is a precondition of
the transform.

This addresses post-commit review on #106216.
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hazzlim authored Oct 4, 2024
1 parent 47c8b95 commit 4da4fac
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Showing 2 changed files with 76 additions and 8 deletions.
5 changes: 1 addition & 4 deletions llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -491,10 +491,7 @@ static bool isArgUnmodifiedByAllCalls(Argument *Arg,
FunctionAnalysisManager &FAM) {
for (User *U : Arg->getParent()->users()) {

// Bail if we find an unexpected (non CallInst) use of the function.
auto *Call = dyn_cast<CallInst>(U);
if (!Call)
return false;
auto *Call = cast<CallBase>(U);

MemoryLocation Loc =
MemoryLocation::getForArgument(Call, Arg->getArgNo(), nullptr);
Expand Down
79 changes: 75 additions & 4 deletions llvm/test/Transforms/ArgumentPromotion/actual-arguments.ll
Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ define internal i32 @test_cannot_promote_1(ptr %p, ptr nocapture readonly %test_
ret i32 %sum
}

; This is called by @caller_aliased_args, from which we can see that %test_c may
; This is called by multiple callers, from which we can see that %test_c may
; alias %p and so we cannot promote %test_c.
;
define internal i32 @test_cannot_promote_2(ptr %p, ptr nocapture readonly %test_c) {
Expand Down Expand Up @@ -87,9 +87,8 @@ define internal i32 @test_can_promote_1(ptr %p, ptr nocapture readonly %test_c)
ret i32 %sum
}

; This is called by multiple callers (@caller_safe_args_1, @caller_safe_args_2),
; from which we can prove that %test_c does not alias %p for any Call to the
; function, so we can promote it.
; This is called by multiple callers, from which we can prove that %test_c does
; not alias %p for any Call to the function, so we can promote it.
;
define internal i32 @test_can_promote_2(ptr %p, ptr nocapture readonly %test_c) {
; CHECK-LABEL: define {{[^@]+}}@test_can_promote_2
Expand Down Expand Up @@ -223,4 +222,76 @@ define i32 @caller_safe_args_2(i64 %n, ptr %p) {
ret i32 %res
}

; Invokes @test_cannot_promote_2
define i32 @caller_invoke_aliased_args() personality ptr @__gxx_personality_v0 {
; CHECK-LABEL: define {{[^@]+}}@caller_invoke_aliased_args() personality ptr @__gxx_personality_v0 {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[CALLER_C:%.*]] = alloca i32, align 4
; CHECK-NEXT: store i32 5, ptr [[CALLER_C]], align 4
; CHECK-NEXT: [[RES:%.*]] = invoke i32 @test_cannot_promote_2(ptr [[CALLER_C]], ptr [[CALLER_C]])
; CHECK-NEXT: to label [[OUT:%.*]] unwind label [[CPAD:%.*]]
; CHECK: out:
; CHECK-NEXT: ret i32 [[RES]]
; CHECK: cpad:
; CHECK-NEXT: [[EXN:%.*]] = landingpad { ptr, i32 }
; CHECK-NEXT: catch ptr @_ZTIi
; CHECK-NEXT: ret i32 -1
;
entry:
%caller_c = alloca i32
store i32 5, ptr %caller_c

%res = invoke i32 @test_cannot_promote_2(ptr %caller_c, ptr %caller_c)
to label %out unwind label %cpad

out:
ret i32 %res

cpad:
%exn = landingpad { ptr, i32 }
catch ptr @_ZTIi
ret i32 -1
}

; Invokes @test_can_promote_2
define i32 @caller_invoke_safe_args(i64 %n) personality ptr @__gxx_personality_v0 {
; CHECK-LABEL: define {{[^@]+}}@caller_invoke_safe_args
; CHECK-SAME: (i64 [[N:%.*]]) personality ptr @__gxx_personality_v0 {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[P:%.*]] = alloca [5 x double], i64 [[N]], align 8
; CHECK-NEXT: call void @memset(ptr [[P]], i64 0, i64 [[N]])
; CHECK-NEXT: [[CALLER_C:%.*]] = alloca i32, align 4
; CHECK-NEXT: store i32 5, ptr [[CALLER_C]], align 4
; CHECK-NEXT: [[CALLER_C_VAL:%.*]] = load i32, ptr [[CALLER_C]], align 4
; CHECK-NEXT: [[RES:%.*]] = invoke i32 @test_can_promote_2(ptr [[P]], i32 [[CALLER_C_VAL]])
; CHECK-NEXT: to label [[OUT:%.*]] unwind label [[CPAD:%.*]]
; CHECK: out:
; CHECK-NEXT: ret i32 [[RES]]
; CHECK: cpad:
; CHECK-NEXT: [[EXN:%.*]] = landingpad { ptr, i32 }
; CHECK-NEXT: catch ptr @_ZTIi
; CHECK-NEXT: ret i32 -1
;
entry:
%p = alloca [5 x double], i64 %n
call void @memset(ptr %p, i64 0, i64 %n)

%caller_c = alloca i32
store i32 5, ptr %caller_c

%res = invoke i32 @test_can_promote_2(ptr %p, ptr %caller_c)
to label %out unwind label %cpad

out:
ret i32 %res

cpad:
%exn = landingpad { ptr, i32 }
catch ptr @_ZTIi
ret i32 -1
}

declare void @memset(ptr, i64, i64)
declare i32 @__gxx_personality_v0(...)

@_ZTIi = external constant ptr

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