2016-08-04 02:17:35 +08:00
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; RUN: llc -verify-machineinstrs < %s | FileCheck %s
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[PowerPC] Load two floats directly instead of using one 64-bit integer load
When dealing with complex<float>, and similar structures with two
single-precision floating-point numbers, especially when such things are being
passed around by value, we'll sometimes end up loading both float values by
extracting them from one 64-bit integer load. It looks like this:
t13: i64,ch = load<LD8[%ref.tmp]> t0, t6, undef:i64
t16: i64 = srl t13, Constant:i32<32>
t17: i32 = truncate t16
t18: f32 = bitcast t17
t19: i32 = truncate t13
t20: f32 = bitcast t19
The problem, especially before the P8 where those bitcasts aren't legal (and
get expanded via the stack), is that it would have been better to use two
floating-point loads directly. Here we add a target-specific DAGCombine to do
just that. In short, we turn:
ld 3, 0(5)
stw 3, -8(1)
rldicl 3, 3, 32, 32
stw 3, -4(1)
lfs 3, -4(1)
lfs 0, -8(1)
into:
lfs 3, 4(5)
lfs 0, 0(5)
llvm-svn: 264988
2016-03-31 10:56:05 +08:00
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target datalayout = "E-m:e-i64:64-n32:64"
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target triple = "powerpc64-bgq-linux"
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define void @_Z4testSt7complexIfE(float %v0, float %v1, i64* %ref.tmp, float* %_M_value.realp.i.i, float* %_M_value.imagp.i.i) {
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entry:
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%v2 = load i64, i64* %ref.tmp, align 8
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%v3 = lshr i64 %v2, 32
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%v4 = trunc i64 %v3 to i32
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%v5 = bitcast i32 %v4 to float
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%v6 = trunc i64 %v2 to i32
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%v7 = bitcast i32 %v6 to float
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%mul_ad.i.i = fmul fast float %v5, %v1
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%mul_bc.i.i = fmul fast float %v7, %v0
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%mul_i.i.i = fadd fast float %mul_ad.i.i, %mul_bc.i.i
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%mul_ac.i.i = fmul fast float %v5, %v0
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%mul_bd.i.i = fmul fast float %v7, %v1
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%mul_r.i.i = fsub fast float %mul_ac.i.i, %mul_bd.i.i
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store float %mul_r.i.i, float* %_M_value.realp.i.i, align 4
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store float %mul_i.i.i, float* %_M_value.imagp.i.i, align 4
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ret void
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; CHECK-LABEL: @_Z4testSt7complexIfE
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; CHECK-NOT: ld {{[0-9]+}}, 0(5)
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; CHECK-NOT: stw
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; CHECK-NOT: rldicl
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; CHECK-DAG: lfs {{[0-9]+}}, 4(5)
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; CHECK-DAG: lfs {{[0-9]+}}, 0(5)
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; CHECK: blr
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}
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define i64* @_Z4testSt7complexIfE_idx(float %v0, float %v1, i64* %ref.tmp, float* %_M_value.realp.i.i, float* %_M_value.imagp.i.i) {
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entry:
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%r = getelementptr i64, i64* %ref.tmp, i64 1
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%v2 = load i64, i64* %r, align 8
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%v3 = lshr i64 %v2, 32
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%v4 = trunc i64 %v3 to i32
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%v5 = bitcast i32 %v4 to float
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%v6 = trunc i64 %v2 to i32
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%v7 = bitcast i32 %v6 to float
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%mul_ad.i.i = fmul fast float %v5, %v1
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%mul_bc.i.i = fmul fast float %v7, %v0
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%mul_i.i.i = fadd fast float %mul_ad.i.i, %mul_bc.i.i
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%mul_ac.i.i = fmul fast float %v5, %v0
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%mul_bd.i.i = fmul fast float %v7, %v1
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%mul_r.i.i = fsub fast float %mul_ac.i.i, %mul_bd.i.i
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store float %mul_r.i.i, float* %_M_value.realp.i.i, align 4
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store float %mul_i.i.i, float* %_M_value.imagp.i.i, align 4
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ret i64* %r
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; CHECK-LABEL: @_Z4testSt7complexIfE
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; CHECK-NOT: ld {{[0-9]+}}, 8(5)
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; CHECK-NOT: ldu {{[0-9]+}}, 8(5)
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; CHECK-NOT: stw
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; CHECK-NOT: rldicl
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; CHECK-DAG: lfsu {{[0-9]+}}, 8(5)
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; CHECK-DAG: lfs {{[0-9]+}}, 4(5)
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; CHECK: blr
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}
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