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Bjorn Pettersson 72e765907f [ConstantFolding] Avoid assert when folding ptrtoint of vectorized GEP
Summary:
Got asserts in llvm::CastInst::getCastOpcode saying:
`DestBits == SrcBits && "Illegal cast to vector (wrong type or size)"' failed.

Problem seemed to be that llvm::ConstantFoldCastInstruction did
not handle ptrtoint cast of a getelementptr returning a vector
correctly. I assume such situations are quite rare, since the
GEP needs to be considered as a constant value (base pointer
being null).
The solution used here is to simply avoid the constant fold
of ptrtoint when the value is a vector. It is not supported,
and by bailing out we do not fail on assertions later on.

Reviewers: craig.topper, majnemer, davide, filcab, efriedma

Reviewed By: efriedma

Subscribers: efriedma, filcab, llvm-commits

Differential Revision: https://reviews.llvm.org/D38546

llvm-svn: 316430
2017-10-24 12:08:11 +00:00

33 lines
1.3 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instsimplify -S | FileCheck %s
; Test constant fold of constant expression GEP used by ptrtoint (the
; "offsetof-like expression" case).
; This used to hit an assert due to not supporting vectors in
; llvm::ConstantFoldCastInstruction when handling ptrtoint.
define <2 x i16> @test1() {
; CHECK-LABEL: @test1(
; CHECK-NEXT: entry:
; CHECK-NEXT: ret <2 x i16> ptrtoint (<2 x i32*> getelementptr ([10 x i32], [10 x i32]* null, <2 x i64> zeroinitializer, <2 x i64> <i64 5, i64 7>) to <2 x i16>)
;
entry:
%gep = getelementptr inbounds [10 x i32], [10 x i32]* null, i16 0, <2 x i16> <i16 5, i16 7>
%vec = ptrtoint <2 x i32*> %gep to <2 x i16>
ret <2 x i16> %vec
}
; Test constant fold of constant expression GEP used by ptrtoint (the
; "sizeof-like expression" case).
; This used to hit an assert due to not supporting vectors in
; llvm::ConstantFoldCastInstruction when handling ptrtoint.
define <2 x i16> @test2() {
; CHECK-LABEL: @test2(
; CHECK-NEXT: entry:
; CHECK-NEXT: ret <2 x i16> ptrtoint (<2 x i32*> getelementptr (i32, i32* null, <2 x i64> <i64 5, i64 7>) to <2 x i16>)
;
entry:
%gep = getelementptr i32, i32* null, <2 x i16> <i16 5, i16 7>
%vec = ptrtoint <2 x i32*> %gep to <2 x i16>
ret <2 x i16> %vec
}