Added a slew of SimplifyInstruction floating-point optimizations, many of which take advantage of fast-math flags. Test cases included.
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
llvm-svn: 169940
diff --git a/llvm/test/Transforms/InstSimplify/fast-math.ll b/llvm/test/Transforms/InstSimplify/fast-math.ll
index e4b3ea3..154b967 100644
--- a/llvm/test/Transforms/InstSimplify/fast-math.ll
+++ b/llvm/test/Transforms/InstSimplify/fast-math.ll
@@ -33,3 +33,75 @@
; 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
+}