llvm-6502/test/CodeGen/AArch64/arm64-fixed-point-scalar-cvt-dagcombine.ll
Ahmed Bougacha 0f1a21bcb8 [AArch64] Prefer DUP/MOV ("CPY") to INS for vector_extract.
This avoids a partial false dependency on the previous content of
the upper lanes of the destination vector register.

Differential Revision: http://reviews.llvm.org/D7307


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227820 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-02 17:55:57 +00:00

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LLVM

; RUN: llc < %s -march=arm64 -aarch64-neon-syntax=apple | FileCheck %s
; DAGCombine to transform a conversion of an extract_vector_elt to an
; extract_vector_elt of a conversion, which saves a round trip of copies
; of the value to a GPR and back to and FPR.
; rdar://11855286
define double @foo0(<2 x i64> %a) nounwind {
; CHECK: scvtf.2d [[REG:v[0-9]+]], v0, #9
; CHECK-NEXT: mov d0, [[REG]][1]
%vecext = extractelement <2 x i64> %a, i32 1
%fcvt_n = tail call double @llvm.aarch64.neon.vcvtfxs2fp.f64.i64(i64 %vecext, i32 9)
ret double %fcvt_n
}
declare double @llvm.aarch64.neon.vcvtfxs2fp.f64.i64(i64, i32) nounwind readnone