llvm-6502/test/CodeGen/PowerPC/fma.ll
Hal Finkel c404e8208c Optionally enable more-aggressive FMA formation in DAGCombine
The heuristic used by DAGCombine to form FMAs checks that the FMUL has only one
use, but this is overly-conservative on some systems. Specifically, if the FMA
and the FADD have the same latency (and the FMA does not compete for resources
with the FMUL any more than the FADD does), there is no need for the
restriction, and furthermore, forming the FMA leaving the FMUL can still allow
for higher overall throughput and decreased critical-path length.

Here we add a new TLI callback, enableAggressiveFMAFusion, false by default, to
elide the hasOneUse check. This is enabled for PowerPC by default, as most
PowerPC systems will benefit.

Patch by Olivier Sallenave, thanks!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218120 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-19 11:42:56 +00:00

93 lines
2.6 KiB
LLVM

; RUN: llc < %s -march=ppc32 -fp-contract=fast | FileCheck %s
declare double @dummy1(double) #0
declare double @dummy2(double, double) #0
declare double @dummy3(double, double, double) #0
define double @test_FMADD1(double %A, double %B, double %C) {
%D = fmul double %A, %B ; <double> [#uses=1]
%E = fadd double %C, %D ; <double> [#uses=1]
ret double %E
; CHECK-LABEL: test_FMADD1:
; CHECK: fmadd
; CHECK-NEXT: blr
}
define double @test_FMADD2(double %A, double %B, double %C) {
%D = fmul double %A, %B ; <double> [#uses=1]
%E = fadd double %D, %C ; <double> [#uses=1]
ret double %E
; CHECK-LABEL: test_FMADD2:
; CHECK: fmadd
; CHECK-NEXT: blr
}
define double @test_FMSUB1(double %A, double %B, double %C) {
%D = fmul double %A, %B ; <double> [#uses=1]
%E = fsub double %D, %C ; <double> [#uses=1]
ret double %E
; CHECK-LABEL: test_FMSUB1:
; CHECK: fmsub
; CHECK-NEXT: blr
}
define double @test_FMSUB2(double %A, double %B, double %C, double %D) {
%E = fmul double %A, %B ; <double> [#uses=2]
%F = fadd double %E, %C ; <double> [#uses=1]
%G = fsub double %E, %D ; <double> [#uses=1]
%H = call double @dummy2(double %F, double %G) ; <double> [#uses=1]
ret double %H
; CHECK-LABEL: test_FMSUB2:
; CHECK: fmadd
; CHECK-NEXT: fmsub
}
define double @test_FNMADD1(double %A, double %B, double %C) {
%D = fmul double %A, %B ; <double> [#uses=1]
%E = fadd double %D, %C ; <double> [#uses=1]
%F = fsub double -0.000000e+00, %E ; <double> [#uses=1]
ret double %F
; CHECK-LABEL: test_FNMADD1:
; CHECK: fnmadd
; CHECK-NEXT: blr
}
define double @test_FNMADD2(double %A, double %B, double %C) {
%D = fmul double %A, %B ; <double> [#uses=1]
%E = fadd double %C, %D ; <double> [#uses=1]
%F = fsub double -0.000000e+00, %E ; <double> [#uses=1]
ret double %F
; CHECK-LABEL: test_FNMADD2:
; CHECK: fnmadd
; CHECK-NEXT: blr
}
define double @test_FNMSUB1(double %A, double %B, double %C) {
%D = fmul double %A, %B ; <double> [#uses=1]
%E = fsub double %C, %D ; <double> [#uses=1]
ret double %E
; CHECK-LABEL: test_FNMSUB1:
; CHECK: fnmsub
; CHECK-NEXT: blr
}
define double @test_FNMSUB2(double %A, double %B, double %C) {
%D = fmul double %A, %B ; <double> [#uses=1]
%E = fsub double %D, %C ; <double> [#uses=1]
%F = fsub double -0.000000e+00, %E ; <double> [#uses=1]
ret double %F
; CHECK-LABEL: test_FNMSUB2:
; CHECK: fnmsub
; CHECK-NEXT: blr
}
define float @test_FNMSUBS(float %A, float %B, float %C) {
%D = fmul float %A, %B ; <float> [#uses=1]
%E = fsub float %D, %C ; <float> [#uses=1]
%F = fsub float -0.000000e+00, %E ; <float> [#uses=1]
ret float %F
; CHECK-LABEL: test_FNMSUBS:
; CHECK: fnmsubs
; CHECK-NEXT: blr
}