llvm/test/CodeGen/X86/no-sse2-avg.ll
Dimitry Andric f9f8cdc1e4 Only attempt to detect AVG if SSE2 is available
Summary:
In PR29973 Sanjay Patel reported an assertion failure when a certain
loop was optimized, for a target without SSE2 support.  It turned out
this was because of the AVG pattern detection introduced in rL253952.

Prevent the assertion failure by bailing out early in
`detectAVGPattern()`, if the target does not support SSE2.

Also add a minimized test case.

Reviewers: congh, eli.friedman, spatel

Subscribers: emaste, llvm-commits

Differential Revision: http://reviews.llvm.org/D20905


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271548 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-02 17:30:49 +00:00

33 lines
1.2 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; REQUIRES: asserts
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=-sse2 | FileCheck %s
define <16 x i8> @PR27973() {
; CHECK-LABEL: PR27973:
; CHECK: # BB#0:
; CHECK-NEXT: movb $0, 15(%rdi)
; CHECK-NEXT: movb $0, 14(%rdi)
; CHECK-NEXT: movb $0, 13(%rdi)
; CHECK-NEXT: movb $0, 12(%rdi)
; CHECK-NEXT: movb $0, 11(%rdi)
; CHECK-NEXT: movb $0, 10(%rdi)
; CHECK-NEXT: movb $0, 9(%rdi)
; CHECK-NEXT: movb $0, 8(%rdi)
; CHECK-NEXT: movb $0, 7(%rdi)
; CHECK-NEXT: movb $0, 6(%rdi)
; CHECK-NEXT: movb $0, 5(%rdi)
; CHECK-NEXT: movb $0, 4(%rdi)
; CHECK-NEXT: movb $0, 3(%rdi)
; CHECK-NEXT: movb $0, 2(%rdi)
; CHECK-NEXT: movb $0, 1(%rdi)
; CHECK-NEXT: movb $0, (%rdi)
; CHECK-NEXT: movq %rdi, %rax
; CHECK-NEXT: retq
;
%t0 = zext <16 x i8> zeroinitializer to <16 x i32>
%t1 = add nuw nsw <16 x i32> %t0, <i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1>
%t2 = lshr <16 x i32> %t1, <i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1>
%t3 = trunc <16 x i32> %t2 to <16 x i8>
ret <16 x i8> %t3
}