b17754bcaa
Since the backend's codegen is capable to expand powi into fmul's, it is not needed anymore to do so in the ::optimizePow() function of SimplifyLibCalls.cpp. What is sufficient is to always turn pow(x, n) into powi(x, n) for the cases where n is a constant integer value. Dropping the current expansion code allowed relaxation of the folding conditions and now this can also happen at optimization levels below Ofast. The added CodeGen/AArch64/powi.ll test case ensures that powi is actually expanded into fmul's, confirming that this refactor did not cause any performance degradation. Following an idea proposed by David Sherwood <david.sherwood@arm.com>. Differential Revision: https://reviews.llvm.org/D128591
26 lines
718 B
LLVM
26 lines
718 B
LLVM
; RUN: llc < %s -mtriple=aarch64-- | FileCheck %s
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declare double @llvm.powi.f64.i32(double, i32)
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declare float @llvm.powi.f32.i32(float, i32)
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declare float @pow(double noundef, double noundef)
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define float @powi_f32(float %x) nounwind {
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; CHECK-LABEL: powi_f32:
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; CHECK: // %bb.0:
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; CHECK-NEXT: fmul s0, s0, s0
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; CHECK-NEXT: fmul s0, s0, s0
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; CHECK-NEXT: ret
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%1 = tail call float @llvm.powi.f32.i32(float %x, i32 4)
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ret float %1
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}
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define double @powi_f64(double %x) nounwind {
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; CHECK-LABEL: powi_f64:
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; CHECK: // %bb.0:
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; CHECK-NEXT: fmul d1, d0, d0
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; CHECK-NEXT: fmul d0, d0, d1
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; CHECK-NEXT: ret
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%1 = tail call double @llvm.powi.f64.i32(double %x, i32 3)
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ret double %1
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}
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