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llvm-mirror/test/CodeGen/ARM/vcvt_combine.ll
Chad Rosier 3127a19140 The Neon VCVT (between floating-point and fixed-point, Advanced SIMD)
instructions can be used to match combinations of multiply/divide and VCVT 
(between floating-point and integer, Advanced SIMD).  Basically the VCVT 
immediate operand that specifies the number of fraction bits corresponds to a 
floating-point multiply or divide by the corresponding power of 2.

For example, VCVT (floating-point to fixed-point, Advanced SIMD) can replace a 
combination of VMUL and VCVT (floating-point to integer) as follows:

Example (assume d17 = <float 8.000000e+00, float 8.000000e+00>):
  vmul.f32        d16, d17, d16
  vcvt.s32.f32    d16, d16
becomes:
  vcvt.s32.f32    d16, d16, #3

Similarly, VCVT (fixed-point to floating-point, Advanced SIMD) can replace a 
combinations of VCVT (integer to floating-point) and VDIV as follows:

Example (assume d17 = <float 8.000000e+00, float 8.000000e+00>):
  vcvt.f32.s32    d16, d16
  vdiv.f32        d16, d17, d16
becomes:
  vcvt.f32.s32    d16, d16, #3

llvm-svn: 133813
2011-06-24 19:23:04 +00:00

100 lines
3.5 KiB
LLVM

; RUN: llc < %s -mtriple=armv7-apple-ios | FileCheck %s
@in = global float 0x400921FA00000000, align 4
; Test signed conversion.
; CHECK: t0
; CHECK-NOT: vmul
define void @t0() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <2 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <2 x float> %vecinit.i, float %tmp, i32 1
%mul.i = fmul <2 x float> %vecinit2.i, <float 8.000000e+00, float 8.000000e+00>
%vcvt.i = fptosi <2 x float> %mul.i to <2 x i32>
tail call void @foo_int32x2_t(<2 x i32> %vcvt.i) nounwind
ret void
}
declare void @foo_int32x2_t(<2 x i32>)
; Test unsigned conversion.
; CHECK: t1
; CHECK-NOT: vmul
define void @t1() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <2 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <2 x float> %vecinit.i, float %tmp, i32 1
%mul.i = fmul <2 x float> %vecinit2.i, <float 8.000000e+00, float 8.000000e+00>
%vcvt.i = fptoui <2 x float> %mul.i to <2 x i32>
tail call void @foo_uint32x2_t(<2 x i32> %vcvt.i) nounwind
ret void
}
declare void @foo_uint32x2_t(<2 x i32>)
; Test which should not fold due to non-power of 2.
; CHECK: t2
; CHECK: vmul
define void @t2() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <2 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <2 x float> %vecinit.i, float %tmp, i32 1
%mul.i = fmul <2 x float> %vecinit2.i, <float 0x401B333340000000, float 0x401B333340000000>
%vcvt.i = fptosi <2 x float> %mul.i to <2 x i32>
tail call void @foo_int32x2_t(<2 x i32> %vcvt.i) nounwind
ret void
}
; Test which should not fold due to power of 2 out of range.
; CHECK: t3
; CHECK: vmul
define void @t3() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <2 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <2 x float> %vecinit.i, float %tmp, i32 1
%mul.i = fmul <2 x float> %vecinit2.i, <float 0x4200000000000000, float 0x4200000000000000>
%vcvt.i = fptosi <2 x float> %mul.i to <2 x i32>
tail call void @foo_int32x2_t(<2 x i32> %vcvt.i) nounwind
ret void
}
; Test which case where const is max power of 2 (i.e., 2^32).
; CHECK: t4
; CHECK-NOT: vmul
define void @t4() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <2 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <2 x float> %vecinit.i, float %tmp, i32 1
%mul.i = fmul <2 x float> %vecinit2.i, <float 0x41F0000000000000, float 0x41F0000000000000>
%vcvt.i = fptosi <2 x float> %mul.i to <2 x i32>
tail call void @foo_int32x2_t(<2 x i32> %vcvt.i) nounwind
ret void
}
; Test quadword.
; CHECK: t5
; CHECK-NOT: vmul
define void @t5() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <4 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <4 x float> %vecinit.i, float %tmp, i32 1
%vecinit4.i = insertelement <4 x float> %vecinit2.i, float %tmp, i32 2
%vecinit6.i = insertelement <4 x float> %vecinit4.i, float %tmp, i32 3
%mul.i = fmul <4 x float> %vecinit6.i, <float 8.000000e+00, float 8.000000e+00, float 8.000000e+00, float 8.000000e+00>
%vcvt.i = fptosi <4 x float> %mul.i to <4 x i32>
tail call void @foo_int32x4_t(<4 x i32> %vcvt.i) nounwind
ret void
}
declare void @foo_int32x4_t(<4 x i32>)
!0 = metadata !{metadata !"float", metadata !1}
!1 = metadata !{metadata !"omnipotent char", metadata !2}
!2 = metadata !{metadata !"Simple C/C++ TBAA", null}