llvm/test/CodeGen/X86/pr26625.ll
Dimitry Andric af4a98fed6 Fix incorrect selection of AVX512 sqrt when OptForSize is on
Summary:
When optimizing for size, sqrt calls can be incorrectly selected as
AVX512 VSQRT instructions.  This is because X86InstrAVX512.td has a
`Requires<[OptForSize]>` in its `avx512_sqrt_scalar` multiclass
definition.  Even if the target does not support AVX512, the class can
apparently still be chosen, leading to an incorrect selection of
`vsqrtss`.

In PR26625, this lead to an assertion: Reg >= X86::FP0 && Reg <=
X86::FP6 && "Expected FP register!", because the `vsqrtss` instruction
requires an XMM register, which is not available on i686 CPUs.

Reviewers: grosbach, resistor, joker.eph

Subscribers: spatel, emaste, llvm-commits

Differential Revision: http://reviews.llvm.org/D17414

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261360 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-19 20:14:11 +00:00

21 lines
453 B
LLVM

; RUN: llc < %s -mcpu=i686 2>&1 | FileCheck %s
; PR26625
target datalayout = "e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128"
target triple = "i386"
define float @x0(float %f) #0 {
entry:
%call = tail call float @sqrtf(float %f) #1
ret float %call
; CHECK-LABEL: x0:
; CHECK: flds
; CHECK-NEXT: fsqrt
; CHECK-NOT: vsqrtss
}
declare float @sqrtf(float) #0
attributes #0 = { nounwind optsize readnone }
attributes #1 = { nounwind optsize readnone }