llvm-6502/test/CodeGen/X86/uint64-to-float.ll
Owen Anderson 3a9e7690ba Use a more efficient lowering of uint64_t --> float that can take advantage of hardware signed integer conversion without
having to do a double cast (uint64_t --> double --> float).  This is based on the algorithm from compiler_rt's __floatundisf
for X86-64.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115634 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-05 17:24:05 +00:00

22 lines
662 B
LLVM

; RUN: llc < %s -march=x86-64 | FileCheck %s
; Verify that we are using the efficient uitofp --> sitofp lowering illustrated
; by the compiler_rt implementation of __floatundisf.
; <rdar://problem/8493982>
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-apple-darwin10.0.0"
; CHECK: testq %rdi, %rdi
; CHECK-NEXT: jns LBB0_2
; CHECK: shrq
; CHECK-NEXT: andq
; CHECK-NEXT: orq
; CHECK-NEXT: cvtsi2ss
; CHECK: LBB0_2
; CHECK-NEXT: cvtsi2ss
define float @test(i64 %a) {
entry:
%b = uitofp i64 %a to float
ret float %b
}