[NFC][InstCombine] 'subtract from one hands of select' pattern tests (PR44426)

https://bugs.llvm.org/show_bug.cgi?id=44426

2 files changed, 78 insertions, 11 deletions

diff --git a/llvm/test/Transforms/InstCombine/subtract-from-one-hand-of-select.ll b/llvm/test/Transforms/InstCombine/subtract-from-one-hand-of-select.ll
new file mode 100644
index 00000000000..1e68efa8bc5
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/subtract-from-one-hand-of-select.ll
@@ -0,0 +1,78 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S < %s -instcombine | FileCheck %s
+
+; Fold
+;   sub %Op0, (select %Cond, %TrueVal, %FalseVal)
+; to
+;   select %Cond, (sub %Op0, %TrueVal), (sub %Op0, %FalseVal)
+
+; https://bugs.llvm.org/show_bug.cgi?id=44426
+
+; Base tests
+
+define i8 @t0_sub_from_trueval(i1 %c, i8 %Op0, i8 %FalseVal) {
+; CHECK-LABEL: @t0_sub_from_trueval(
+; CHECK-NEXT:    [[O:%.*]] = select i1 [[C:%.*]], i8 [[OP0:%.*]], i8 [[FALSEVAL:%.*]], !prof !0
+; CHECK-NEXT:    [[R:%.*]] = sub i8 [[OP0]], [[O]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %o = select i1 %c, i8 %Op0, i8 %FalseVal, !prof !0 ; while there, ensure preservation of prof md
+  %r = sub i8 %Op0, %o
+  ret i8 %r
+}
+define i8 @t1_sub_from_falseval(i1 %c, i8 %TrueVal, i8 %Op0) {
+; CHECK-LABEL: @t1_sub_from_falseval(
+; CHECK-NEXT:    [[O:%.*]] = select i1 [[C:%.*]], i8 [[TRUEVAL:%.*]], i8 [[OP0:%.*]], !prof !0
+; CHECK-NEXT:    [[R:%.*]] = sub i8 [[OP0]], [[O]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %o = select i1 %c, i8 %TrueVal, i8 %Op0, !prof !0 ; while there, ensure preservation of prof md
+  %r = sub i8 %Op0, %o
+  ret i8 %r
+}
+
+; Vectors
+
+define <2 x i8> @t2_vec(i1 %c, <2 x i8> %Op0, <2 x i8> %FalseVal) {
+; CHECK-LABEL: @t2_vec(
+; CHECK-NEXT:    [[O:%.*]] = select i1 [[C:%.*]], <2 x i8> [[OP0:%.*]], <2 x i8> [[FALSEVAL:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = sub <2 x i8> [[OP0]], [[O]]
+; CHECK-NEXT:    ret <2 x i8> [[R]]
+;
+  %o = select i1 %c, <2 x i8> %Op0, <2 x i8> %FalseVal
+  %r = sub <2 x i8> %Op0, %o
+  ret <2 x i8> %r
+}
+
+; Extra use
+
+declare void @use8(i8)
+
+define i8 @n3_extrause(i1 %c, i8 %Op0, i8 %FalseVal) {
+; CHECK-LABEL: @n3_extrause(
+; CHECK-NEXT:    [[O:%.*]] = select i1 [[C:%.*]], i8 [[OP0:%.*]], i8 [[FALSEVAL:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[O]])
+; CHECK-NEXT:    [[R:%.*]] = sub i8 [[OP0]], [[O]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %o = select i1 %c, i8 %Op0, i8 %FalseVal
+  call void @use8(i8 %o)
+  %r = sub i8 %Op0, %o
+  ret i8 %r
+}
+
+; Negative tests
+
+define i8 @n4_wrong_hands(i1 %c, i8 %TrueVal, i8 %FalseVal, i8 %Op0) {
+; CHECK-LABEL: @n4_wrong_hands(
+; CHECK-NEXT:    [[O:%.*]] = select i1 [[C:%.*]], i8 [[TRUEVAL:%.*]], i8 [[FALSEVAL:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = sub i8 [[OP0:%.*]], [[O]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %o = select i1 %c, i8 %TrueVal, i8 %FalseVal ; none of the hands is %Op0
+  %r = sub i8 %Op0, %o
+  ret i8 %r
+}
+
+; CHECK: !0 = !{!"branch_weights", i32 0, i32 100}
+!0  = !{!"branch_weights", i32 0, i32 100}
diff --git a/llvm/test/Transforms/InstCombine/subtract-of-one-hand-of-select.ll b/llvm/test/Transforms/InstCombine/subtract-of-one-hand-of-select.ll
index 931a7e9d2c0..cfe35f06bd1 100644
--- a/llvm/test/Transforms/InstCombine/subtract-of-one-hand-of-select.ll
+++ b/llvm/test/Transforms/InstCombine/subtract-of-one-hand-of-select.ll
@@ -74,16 +74,5 @@ define i8 @n4_wrong_hands(i1 %c, i8 %TrueVal, i8 %FalseVal, i8 %Op1) {
   ret i8 %r
 }
 
-define i8 @n5_wrong_sub(i1 %c, i8 %Op1, i8 %FalseVal) {
-; CHECK-LABEL: @n5_wrong_sub(
-; CHECK-NEXT:    [[O:%.*]] = select i1 [[C:%.*]], i8 [[OP1:%.*]], i8 [[FALSEVAL:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = sub i8 [[OP1]], [[O]]
-; CHECK-NEXT:    ret i8 [[R]]
-;
-  %o = select i1 %c, i8 %Op1, i8 %FalseVal
-  %r = sub i8 %Op1, %o ; wrong order
-  ret i8 %r
-}
-
 ; CHECK: !0 = !{!"branch_weights", i32 0, i32 100}
 !0  = !{!"branch_weights", i32 0, i32 100}