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llvm-mirror/test/CodeGen/Mips/llvm-ir/extractelement.ll
Matt Arsenault f633d550ca DAG: Avoid OOB when legalizing vector indexing
If a vector index is out of bounds, the result is supposed to be
undefined but is not undefined behavior. Change the legalization
for indexing the vector on the stack so that an out of bounds
index does not create an out of bounds memory access.

llvm-svn: 291604
2017-01-10 22:02:30 +00:00

21 lines
876 B
LLVM

; RUN: llc < %s -march=mips -mcpu=mips2 | FileCheck %s -check-prefix=ALL
; This test triggered a bug in the vector splitting where the type legalizer
; attempted to extract the element with by storing the vector, then reading
; an element back. However, the address calculation was:
; Base + Index * (EltSizeInBits / 8)
; and EltSizeInBits was 1. This caused the index to be forgotten.
define i1 @via_stack_bug(i8 signext %idx) {
%1 = extractelement <2 x i1> <i1 false, i1 true>, i8 %idx
ret i1 %1
}
; ALL-LABEL: via_stack_bug:
; ALL-DAG: addiu [[ONE:\$[0-9]+]], $zero, 1
; ALL-DAG: sb [[ONE]], 7($sp)
; ALL-DAG: sb $zero, 6($sp)
; ALL-DAG: andi [[MASKED_IDX:\$[0-9]+]], $4, 1
; ALL-DAG: addiu [[VPTR:\$[0-9]+]], $sp, 6
; ALL-DAG: or [[EPTR:\$[0-9]+]], [[MASKED_IDX]], [[VPTR]]
; ALL: lbu $2, 0([[EPTR]])