[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; Test that the pow library call simplifier works correctly.
|
|
|
|
|
|
|
|
; RUN: opt -instcombine -S < %s | FileCheck %s
|
|
|
|
|
|
|
|
; Function Attrs: nounwind readnone
|
|
|
|
declare double @llvm.pow.f64(double, double)
|
|
|
|
declare float @llvm.pow.f32(float, float)
|
|
|
|
|
|
|
|
; pow(x, 4.0f)
|
2016-01-20 02:15:12 +08:00
|
|
|
define float @test_simplify_4f(float %x) {
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; CHECK-LABEL: @test_simplify_4f(
|
|
|
|
; CHECK-NOT: pow
|
|
|
|
; CHECK-NEXT: %1 = fmul float %x, %x
|
|
|
|
; CHECK-NEXT: %2 = fmul float %1, %1
|
|
|
|
; CHECK-NEXT: ret float %2
|
2016-01-20 02:15:12 +08:00
|
|
|
%1 = call fast float @llvm.pow.f32(float %x, float 4.000000e+00)
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
ret float %1
|
|
|
|
}
|
|
|
|
|
|
|
|
; pow(x, 3.0)
|
2016-01-20 02:15:12 +08:00
|
|
|
define double @test_simplify_3(double %x) {
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; CHECK-LABEL: @test_simplify_3(
|
|
|
|
; CHECK-NOT: pow
|
|
|
|
; CHECK-NEXT: %1 = fmul double %x, %x
|
|
|
|
; CHECK-NEXT: %2 = fmul double %1, %x
|
|
|
|
; CHECK-NEXT: ret double %2
|
2016-01-20 02:15:12 +08:00
|
|
|
%1 = call fast double @llvm.pow.f64(double %x, double 3.000000e+00)
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
ret double %1
|
|
|
|
}
|
|
|
|
|
|
|
|
; pow(x, 4.0)
|
2016-01-20 02:15:12 +08:00
|
|
|
define double @test_simplify_4(double %x) {
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; CHECK-LABEL: @test_simplify_4(
|
|
|
|
; CHECK-NOT: pow
|
|
|
|
; CHECK-NEXT: %1 = fmul double %x, %x
|
|
|
|
; CHECK-NEXT: %2 = fmul double %1, %1
|
|
|
|
; CHECK-NEXT: ret double %2
|
2016-01-20 02:15:12 +08:00
|
|
|
%1 = call fast double @llvm.pow.f64(double %x, double 4.000000e+00)
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
ret double %1
|
|
|
|
}
|
|
|
|
|
|
|
|
; pow(x, 15.0)
|
2016-01-20 02:15:12 +08:00
|
|
|
define double @test_simplify_15(double %x) {
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; CHECK-LABEL: @test_simplify_15(
|
|
|
|
; CHECK-NOT: pow
|
|
|
|
; CHECK-NEXT: %1 = fmul double %x, %x
|
|
|
|
; CHECK-NEXT: %2 = fmul double %1, %x
|
|
|
|
; CHECK-NEXT: %3 = fmul double %2, %2
|
|
|
|
; CHECK-NEXT: %4 = fmul double %3, %3
|
|
|
|
; CHECK-NEXT: %5 = fmul double %2, %4
|
|
|
|
; CHECK-NEXT: ret double %5
|
2016-01-20 02:15:12 +08:00
|
|
|
%1 = call fast double @llvm.pow.f64(double %x, double 1.500000e+01)
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
ret double %1
|
|
|
|
}
|
|
|
|
|
|
|
|
; pow(x, -7.0)
|
2016-01-20 02:15:12 +08:00
|
|
|
define double @test_simplify_neg_7(double %x) {
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; CHECK-LABEL: @test_simplify_neg_7(
|
|
|
|
; CHECK-NOT: pow
|
|
|
|
; CHECK-NEXT: %1 = fmul double %x, %x
|
|
|
|
; CHECK-NEXT: %2 = fmul double %1, %x
|
|
|
|
; CHECK-NEXT: %3 = fmul double %1, %2
|
|
|
|
; CHECK-NEXT: %4 = fmul double %1, %3
|
|
|
|
; CHECK-NEXT: %5 = fdiv double 1.000000e+00, %4
|
|
|
|
; CHECK-NEXT: ret double %5
|
2016-01-20 02:15:12 +08:00
|
|
|
%1 = call fast double @llvm.pow.f64(double %x, double -7.000000e+00)
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
ret double %1
|
|
|
|
}
|
|
|
|
|
|
|
|
; pow(x, -19.0)
|
2016-01-20 02:15:12 +08:00
|
|
|
define double @test_simplify_neg_19(double %x) {
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; CHECK-LABEL: @test_simplify_neg_19(
|
|
|
|
; CHECK-NOT: pow
|
|
|
|
; CHECK-NEXT: %1 = fmul double %x, %x
|
|
|
|
; CHECK-NEXT: %2 = fmul double %1, %1
|
|
|
|
; CHECK-NEXT: %3 = fmul double %2, %2
|
|
|
|
; CHECK-NEXT: %4 = fmul double %3, %3
|
|
|
|
; CHECK-NEXT: %5 = fmul double %1, %4
|
|
|
|
; CHECK-NEXT: %6 = fmul double %5, %x
|
|
|
|
; CHECK-NEXT: %7 = fdiv double 1.000000e+00, %6
|
|
|
|
; CHECK-NEXT: ret double %7
|
2016-01-20 02:15:12 +08:00
|
|
|
%1 = call fast double @llvm.pow.f64(double %x, double -1.900000e+01)
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
ret double %1
|
|
|
|
}
|
|
|
|
|
|
|
|
; pow(x, 11.23)
|
2016-01-20 02:15:12 +08:00
|
|
|
define double @test_simplify_11_23(double %x) {
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; CHECK-LABEL: @test_simplify_11_23(
|
|
|
|
; CHECK-NOT: fmul
|
2016-01-20 02:15:12 +08:00
|
|
|
; CHECK-NEXT: %1 = call fast double @llvm.pow.f64(double %x, double 1.123000e+01)
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; CHECK-NEXT: ret double %1
|
2016-01-20 02:15:12 +08:00
|
|
|
%1 = call fast double @llvm.pow.f64(double %x, double 1.123000e+01)
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
ret double %1
|
|
|
|
}
|
|
|
|
|
|
|
|
; pow(x, 32.0)
|
2016-01-20 02:15:12 +08:00
|
|
|
define double @test_simplify_32(double %x) {
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; CHECK-LABEL: @test_simplify_32(
|
|
|
|
; CHECK-NOT: pow
|
|
|
|
; CHECK-NEXT: %1 = fmul double %x, %x
|
|
|
|
; CHECK-NEXT: %2 = fmul double %1, %1
|
|
|
|
; CHECK-NEXT: %3 = fmul double %2, %2
|
|
|
|
; CHECK-NEXT: %4 = fmul double %3, %3
|
|
|
|
; CHECK-NEXT: %5 = fmul double %4, %4
|
|
|
|
; CHECK-NEXT: ret double %5
|
2016-01-20 02:15:12 +08:00
|
|
|
%1 = call fast double @llvm.pow.f64(double %x, double 3.200000e+01)
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
ret double %1
|
|
|
|
}
|
|
|
|
|
|
|
|
; pow(x, 33.0)
|
2016-01-20 02:15:12 +08:00
|
|
|
define double @test_simplify_33(double %x) {
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; CHECK-LABEL: @test_simplify_33(
|
|
|
|
; CHECK-NOT: fmul
|
2016-01-20 02:15:12 +08:00
|
|
|
; CHECK-NEXT: %1 = call fast double @llvm.pow.f64(double %x, double 3.300000e+01)
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
; CHECK-NEXT: ret double %1
|
2016-01-20 02:15:12 +08:00
|
|
|
%1 = call fast double @llvm.pow.f64(double %x, double 3.300000e+01)
|
[SimplifyLibCalls] Optimization for pow(x, n) where n is some constant
Summary:
In order to avoid calling pow function we generate repeated fmul when n is a
positive or negative whole number.
For each exponent we pre-compute Addition Chains in order to minimize the no.
of fmuls.
Refer: http://wwwhomes.uni-bielefeld.de/achim/addition_chain.html
We pre-compute addition chains for exponents upto 32 (which results in a max of
7 fmuls).
For eg:
4 = 2+2
5 = 2+3
6 = 3+3 and so on
Hence,
pow(x, 4.0) ==> y = fmul x, x
x = fmul y, y
ret x
For negative exponents, we simply compute the reciprocal of the final result.
Note: This transformation is only enabled under fast-math.
Patch by Mandeep Singh Grang <mgrang@codeaurora.org>
Reviewers: weimingz, majnemer, escha, davide, scanon, joerg
Subscribers: probinson, escha, llvm-commits
Differential Revision: http://reviews.llvm.org/D13994
llvm-svn: 254776
2015-12-05 06:00:47 +08:00
|
|
|
ret double %1
|
|
|
|
}
|
|
|
|
|