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f3f72e53d7
Summary:
One of the vector splitting paths for extract_vector_elt tries to lower:
define i1 @via_stack_bug(i8 signext %idx) {
%1 = extractelement <2 x i1> <i1 false, i1 true>, i8 %idx
ret i1 %1
}
to:
define i1 @via_stack_bug(i8 signext %idx) {
%base = alloca <2 x i1>
store <2 x i1> <i1 false, i1 true>, <2 x i1>* %base
%2 = getelementptr <2 x i1>, <2 x i1>* %base, i32 %idx
%3 = load i1, i1* %2
ret i1 %3
}
However, the elements of <2 x i1> are not byte-addressible. The result of this
is that the getelementptr expands to '%base + %idx * (1 / 8)' which simplifies
to '%base + %idx * 0', and then simply '%base' causing all values of %idx to
extract element zero.
This commit fixes this by promoting the vector elements of <8-bits to i8 before
splitting the vector.
This fixes a number of test failures in pocl.
Reviewers: pekka.jaaskelainen
Subscribers: pekka.jaaskelainen, llvm-commits
Differential Revision: http://reviews.llvm.org/D12591
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247128 91177308-0d34-0410-b5e6-96231b3b80d8
20 lines
811 B
LLVM
20 lines
811 B
LLVM
; RUN: llc < %s -march=mips -mcpu=mips2 | FileCheck %s -check-prefix=ALL
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; This test triggered a bug in the vector splitting where the type legalizer
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; attempted to extract the element with by storing the vector, then reading
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; an element back. However, the address calculation was:
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; Base + Index * (EltSizeInBits / 8)
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; and EltSizeInBits was 1. This caused the index to be forgotten.
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define i1 @via_stack_bug(i8 signext %idx) {
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%1 = extractelement <2 x i1> <i1 false, i1 true>, i8 %idx
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ret i1 %1
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}
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; ALL-LABEL: via_stack_bug:
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; ALL-DAG: addiu [[ONE:\$[0-9]+]], $zero, 1
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; ALL-DAG: sb [[ONE]], 7($sp)
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; ALL-DAG: sb $zero, 6($sp)
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; ALL-DAG: addiu [[VPTR:\$[0-9]+]], $sp, 6
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; ALL-DAG: addu [[EPTR:\$[0-9]+]], $4, [[VPTR]]
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; ALL: lbu $2, 0([[EPTR]])
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