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llvm-project/llvm/test/CodeGen/X86/fdiv.ll

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Only have codegen turn fdiv by a constant into fmul by the reciprocal when -ffast-math, i.e. don't just always do it if the reciprocal can be formed exactly. There is already an IR level transform that does that, and it does it more carefully. llvm-svn: 154296
2012-04-09 02:08:12 +08:00
; RUN: llc < %s -march=x86-64 -enable-unsafe-fp-math | FileCheck %s
Convert floating point division by a constant into multiplication by the reciprocal if converting to the reciprocal is exact. Do it even if inexact if -ffast-math. This substantially speeds up ac.f90 from the polyhedron benchmarks. llvm-svn: 154265
2012-04-08 04:04:00 +08:00
define double @exact(double %x) {
Only have codegen turn fdiv by a constant into fmul by the reciprocal when -ffast-math, i.e. don't just always do it if the reciprocal can be formed exactly. There is already an IR level transform that does that, and it does it more carefully. llvm-svn: 154296
2012-04-09 02:08:12 +08:00
; Exact division by a constant converted to multiplication.
Convert floating point division by a constant into multiplication by the reciprocal if converting to the reciprocal is exact. Do it even if inexact if -ffast-math. This substantially speeds up ac.f90 from the polyhedron benchmarks. llvm-svn: 154265
2012-04-08 04:04:00 +08:00
; CHECK: @exact
; CHECK: mulsd
%div = fdiv double %x, 2.0
ret double %div
}
define double @inexact(double %x) {
Only have codegen turn fdiv by a constant into fmul by the reciprocal when -ffast-math, i.e. don't just always do it if the reciprocal can be formed exactly. There is already an IR level transform that does that, and it does it more carefully. llvm-svn: 154296
2012-04-09 02:08:12 +08:00
; Inexact division by a constant converted to multiplication.
Convert floating point division by a constant into multiplication by the reciprocal if converting to the reciprocal is exact. Do it even if inexact if -ffast-math. This substantially speeds up ac.f90 from the polyhedron benchmarks. llvm-svn: 154265
2012-04-08 04:04:00 +08:00
; CHECK: @inexact
Only have codegen turn fdiv by a constant into fmul by the reciprocal when -ffast-math, i.e. don't just always do it if the reciprocal can be formed exactly. There is already an IR level transform that does that, and it does it more carefully. llvm-svn: 154296
2012-04-09 02:08:12 +08:00
; CHECK: mulsd
Convert floating point division by a constant into multiplication by the reciprocal if converting to the reciprocal is exact. Do it even if inexact if -ffast-math. This substantially speeds up ac.f90 from the polyhedron benchmarks. llvm-svn: 154265
2012-04-08 04:04:00 +08:00
%div = fdiv double %x, 0x41DFFFFFFFC00000
ret double %div
}
define double @funky(double %x) {
; No conversion to multiplication if too funky.
; CHECK: @funky
; CHECK: divsd
%div = fdiv double %x, 0.0
ret double %div
}
Add a comment noting that the fdiv -> fmul conversion won't generate multiplication by a denormal, and some tests checking that. llvm-svn: 154431
2012-04-11 04:35:27 +08:00
define double @denormal1(double %x) {
; Don't generate multiplication by a denormal.
; CHECK: @denormal1
; CHECK: divsd
%div = fdiv double %x, 0x7FD0000000000001
ret double %div
}
define double @denormal2(double %x) {
; Don't generate multiplication by a denormal.
; CHECK: @denormal
; CHECK: divsd
%div = fdiv double %x, 0x7FEFFFFFFFFFFFFF
ret double %div
}