[InstSimplify] add tests for fadd/fsub; NFC

Instcombine gets some, but not all, of these cases via
it's internal reassociation transforms. It fails in
all cases with vector types.

llvm-svn: 339168

1 files changed, 174 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstSimplify/floating-point-arithmetic.ll b/llvm/test/Transforms/InstSimplify/floating-point-arithmetic.ll
index 79eb349ed7e..0481ee45651 100644
--- a/llvm/test/Transforms/InstSimplify/floating-point-arithmetic.ll
+++ b/llvm/test/Transforms/InstSimplify/floating-point-arithmetic.ll
@@ -733,3 +733,177 @@ define float @maxnum_x_y_maxnum_z(float %x, float %y, float %z) {
   ret float %b
 }
 
+; Y - (Y - X) --> X
+
+define float @fsub_fsub_common_op(float %x, float %y) {
+; CHECK-LABEL: @fsub_fsub_common_op(
+; CHECK-NEXT:    [[S:%.*]] = fsub float [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub reassoc nsz float [[Y]], [[S]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %s = fsub float %y, %x
+  %r = fsub reassoc nsz float %y, %s
+  ret float %r
+}
+
+define <2 x float> @fsub_fsub_common_op_vec(<2 x float> %x, <2 x float> %y) {
+; CHECK-LABEL: @fsub_fsub_common_op_vec(
+; CHECK-NEXT:    [[S:%.*]] = fsub <2 x float> [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub reassoc nsz <2 x float> [[Y]], [[S]]
+; CHECK-NEXT:    ret <2 x float> [[R]]
+;
+  %s = fsub <2 x float> %y, %x
+  %r = fsub reassoc nsz <2 x float> %y, %s
+  ret <2 x float> %r
+}
+
+; Negative test - fsub is not commutative.
+; Y - (X - Y) --> (Y - X) + Y (canonicalized)
+
+define float @fsub_fsub_wrong_common_op(float %x, float %y) {
+; CHECK-LABEL: @fsub_fsub_wrong_common_op(
+; CHECK-NEXT:    [[S:%.*]] = fsub float [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub reassoc nsz float [[Y]], [[S]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %s = fsub float %x, %y
+  %r = fsub reassoc nsz float %y, %s
+  ret float %r
+}
+
+; Negative test - negated operand needed.
+; (Y - X) - Y --> -X
+
+define float @fsub_fsub_common_op_wrong_commute(float %x, float %y) {
+; CHECK-LABEL: @fsub_fsub_common_op_wrong_commute(
+; CHECK-NEXT:    [[S:%.*]] = fsub float [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub reassoc nsz float [[S]], [[Y]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %s = fsub float %y, %x
+  %r = fsub reassoc nsz float %s, %y
+  ret float %r
+}
+
+; Negative test - fsub is not commutative.
+; (X - Y) - Y --> ?
+
+define float @fsub_fsub_wrong_common_op_wrong_commute(float %x, float %y) {
+; CHECK-LABEL: @fsub_fsub_wrong_common_op_wrong_commute(
+; CHECK-NEXT:    [[S:%.*]] = fsub float [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub reassoc nsz float [[S]], [[Y]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %s = fsub float %x, %y
+  %r = fsub reassoc nsz float %s, %y
+  ret float %r
+}
+
+; (Y + X) - Y --> X
+
+define float @fadd_fsub_common_op(float %x, float %y) {
+; CHECK-LABEL: @fadd_fsub_common_op(
+; CHECK-NEXT:    [[A:%.*]] = fadd float [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub reassoc nsz float [[A]], [[Y]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %a = fadd float %y, %x
+  %r = fsub reassoc nsz float %a, %y
+  ret float %r
+}
+
+; (X + Y) - Y --> X
+
+define <2 x float> @fadd_fsub_common_op_commute_vec(<2 x float> %x, <2 x float> %y) {
+; CHECK-LABEL: @fadd_fsub_common_op_commute_vec(
+; CHECK-NEXT:    [[A:%.*]] = fadd <2 x float> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub reassoc nsz <2 x float> [[A]], [[Y]]
+; CHECK-NEXT:    ret <2 x float> [[R]]
+;
+  %a = fadd <2 x float> %x, %y
+  %r = fsub reassoc nsz <2 x float> %a, %y
+  ret <2 x float> %r
+}
+
+; Negative test - negated operand needed.
+; Y - (Y + X) --> -X
+
+define float @fadd_fsub_common_op_wrong_commute(float %x, float %y) {
+; CHECK-LABEL: @fadd_fsub_common_op_wrong_commute(
+; CHECK-NEXT:    [[A:%.*]] = fadd float [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub reassoc nsz float [[Y]], [[A]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %a = fadd float %y, %x
+  %r = fsub reassoc nsz float %y, %a
+  ret float %r
+}
+
+; Negative test - negated operand needed.
+; Y - (X + Y) --> -X
+
+define float @fadd_fsub_common_op_wrong_commute_commute(float %x, float %y) {
+; CHECK-LABEL: @fadd_fsub_common_op_wrong_commute_commute(
+; CHECK-NEXT:    [[A:%.*]] = fadd float [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fsub reassoc nsz float [[Y]], [[A]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %a = fadd float %x, %y
+  %r = fsub reassoc nsz float %y, %a
+  ret float %r
+}
+
+; Y + (X - Y) --> X
+
+define <2 x float> @fsub_fadd_common_op_vec(<2 x float> %x, <2 x float> %y) {
+; CHECK-LABEL: @fsub_fadd_common_op_vec(
+; CHECK-NEXT:    [[S:%.*]] = fsub <2 x float> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fadd reassoc nsz <2 x float> [[Y]], [[S]]
+; CHECK-NEXT:    ret <2 x float> [[R]]
+;
+  %s = fsub <2 x float> %x, %y
+  %r = fadd reassoc nsz <2 x float> %y, %s
+  ret <2 x float> %r
+}
+
+; (X - Y) + Y --> X
+
+define float @fsub_fadd_common_op_commute(float %x, float %y) {
+; CHECK-LABEL: @fsub_fadd_common_op_commute(
+; CHECK-NEXT:    [[S:%.*]] = fsub float [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fadd reassoc nsz float [[S]], [[Y]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %s = fsub float %x, %y
+  %r = fadd reassoc nsz float %s, %y
+  ret float %r
+}
+
+; Negative test.
+; Y + (Y - X) --> ?
+
+define float @fsub_fadd_common_op_wrong_commute(float %x, float %y) {
+; CHECK-LABEL: @fsub_fadd_common_op_wrong_commute(
+; CHECK-NEXT:    [[S:%.*]] = fsub float [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fadd reassoc nsz float [[Y]], [[S]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %s = fsub float %y, %x
+  %r = fadd reassoc nsz float %y, %s
+  ret float %r
+}
+
+; Negative test.
+; (Y - X) + Y --> ?
+
+define float @fsub_fadd_common_op_wrong_commute_commute(float %x, float %y) {
+; CHECK-LABEL: @fsub_fadd_common_op_wrong_commute_commute(
+; CHECK-NEXT:    [[S:%.*]] = fsub float [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = fadd reassoc nsz float [[S]], [[Y]]
+; CHECK-NEXT:    ret float [[R]]
+;
+  %s = fsub float %y, %x
+  %r = fadd reassoc nsz float %s, %y
+  ret float %r
+}
+