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Added a slew of SimplifyInstruction floating-point optimizations, many of which take advantage of fast-math flags. Test cases included.

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fsub X, +0 ==> X
  fsub X, -0 ==> X, when we know X is not -0
  fsub +/-0.0, (fsub -0.0, X) ==> X
  fsub nsz +/-0.0, (fsub +/-0.0, X) ==> X
  fsub nnan ninf X, X ==> 0.0
  fadd nsz X, 0 ==> X
  fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
    where nnan and ninf have to occur at least once somewhere in this expression
  fmul X, 1.0 ==> X



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169940 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Michael Ilseman
2012-12-12 00:27:46 +00:00
parent 1d4b150704
commit 09ee250e72
4 changed files with 230 additions and 10 deletions
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72
test/Transforms/InstSimplify/fast-math.ll
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@@ -33,3 +33,75 @@ define float @no_mul_zero_3(float %a) {
; CHECK: ret float %b
ret float %b
}
; fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
; where nnan and ninf have to occur at least once somewhere in this
; expression
; CHECK: fadd_fsub_0
define float @fadd_fsub_0(float %a) {
; X + -X ==> 0
%t1 = fsub nnan ninf float 0.0, %a
%zero1 = fadd nnan ninf float %t1, %a
%t2 = fsub nnan float 0.0, %a
%zero2 = fadd ninf float %t2, %a
%t3 = fsub nnan ninf float 0.0, %a
%zero3 = fadd float %t3, %a
%t4 = fsub float 0.0, %a
%zero4 = fadd nnan ninf float %t4, %a
; Dont fold this
; CHECK: %nofold = fsub float 0.0
%nofold = fsub float 0.0, %a
; CHECK: %no_zero = fadd nnan float %nofold, %a
%no_zero = fadd nnan float %nofold, %a
; Coalesce the folded zeros
%zero5 = fadd float %zero1, %zero2
%zero6 = fadd float %zero3, %zero4
%zero7 = fadd float %zero5, %zero6
; Should get folded
%ret = fadd nsz float %no_zero, %zero7
; CHECK: ret float %no_zero
ret float %ret
}
; fsub nnan ninf x, x ==> 0.0
; CHECK: @fsub_x_x
define float @fsub_x_x(float %a) {
; X - X ==> 0
%zero1 = fsub nnan ninf float %a, %a
; Dont fold
; CHECK: %no_zero1 = fsub
%no_zero1 = fsub ninf float %a, %a
; CHECK: %no_zero2 = fsub
%no_zero2 = fsub nnan float %a, %a
; CHECK: %no_zero = fadd
%no_zero = fadd float %no_zero1, %no_zero2
; Should get folded
%ret = fadd nsz float %no_zero, %zero1
; CHECK: ret float %no_zero
ret float %ret
}
; fadd nsz X, 0 ==> X
; CHECK: @nofold_fadd_x_0
define float @nofold_fadd_x_0(float %a) {
; Dont fold
; CHECK: %no_zero1 = fadd
%no_zero1 = fadd ninf float %a, 0.0
; CHECK: %no_zero2 = fadd
%no_zero2 = fadd nnan float %a, 0.0
; CHECK: %no_zero = fadd
%no_zero = fadd float %no_zero1, %no_zero2
; CHECK: ret float %no_zero
ret float %no_zero
}