[InstCombine] add tests for umin+icmp; NFC

llvm-svn: 289157

1 files changed, 258 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/umin-icmp.ll b/llvm/test/Transforms/InstCombine/umin-icmp.ll
new file mode 100644
index 00000000000..f9d814d0d99
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/umin-icmp.ll
@@ -0,0 +1,258 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -instcombine < %s | FileCheck %s
+
+; If we have a umin feeding an unsigned or equality icmp that shares an
+; operand with the umin, the compare should always be folded.
+; Test all 4 foldable predicates (eq,ne,uge,ult) * 4 commutation
+; possibilities for each predicate. Note that folds to true/false 
+; (predicate is ule/ugt) or folds to an existing instruction should be
+; handled by InstSimplify.
+
+; umin(X, Y) == X --> X <= Y
+
+define i1 @eq_umin1(i32 %x, i32 %y) {
+; CHECK-LABEL: @eq_umin1(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 %x, %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %x, i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i32 [[SEL]], %x
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = icmp ult i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp eq i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Commute min operands.
+
+define i1 @eq_umin2(i32 %x, i32 %y) {
+; CHECK-LABEL: @eq_umin2(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 %y, %x
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %y, i32 %x
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i32 [[SEL]], %x
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = icmp ult i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp eq i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Disguise the icmp predicate by commuting the min op to the RHS.
+
+define i1 @eq_umin3(i32 %a, i32 %y) {
+; CHECK-LABEL: @eq_umin3(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 [[X]], %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i32 [[X]], [[SEL]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp ult i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp eq i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; Commute min operands.
+
+define i1 @eq_umin4(i32 %a, i32 %y) {
+; CHECK-LABEL: @eq_umin4(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ugt i32 [[X]], %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %y, i32 [[X]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq i32 [[X]], [[SEL]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp ult i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp eq i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; umin(X, Y) >= X --> X <= Y
+
+define i1 @uge_umin1(i32 %x, i32 %y) {
+; CHECK-LABEL: @uge_umin1(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 %x, %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %x, i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp uge i32 [[SEL]], %x
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = icmp ult i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp uge i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Commute min operands.
+
+define i1 @uge_umin2(i32 %x, i32 %y) {
+; CHECK-LABEL: @uge_umin2(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 %y, %x
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %y, i32 %x
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp uge i32 [[SEL]], %x
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = icmp ult i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp uge i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Disguise the icmp predicate by commuting the min op to the RHS.
+
+define i1 @uge_umin3(i32 %a, i32 %y) {
+; CHECK-LABEL: @uge_umin3(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 [[X]], %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ule i32 [[X]], [[SEL]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp ult i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp ule i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; Commute min operands.
+
+define i1 @uge_umin4(i32 %a, i32 %y) {
+; CHECK-LABEL: @uge_umin4(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ugt i32 [[X]], %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %y, i32 [[X]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ule i32 [[X]], [[SEL]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp ult i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp ule i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; umin(X, Y) != X --> X > Y
+
+define i1 @ne_umin1(i32 %x, i32 %y) {
+; CHECK-LABEL: @ne_umin1(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 %x, %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %x, i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ne i32 [[SEL]], %x
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = icmp ult i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp ne i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Commute min operands.
+
+define i1 @ne_umin2(i32 %x, i32 %y) {
+; CHECK-LABEL: @ne_umin2(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 %y, %x
+; CHECK-NEXT:    ret i1 [[CMP1]]
+;
+  %cmp1 = icmp ult i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp ne i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Disguise the icmp predicate by commuting the min op to the RHS.
+
+define i1 @ne_umin3(i32 %a, i32 %y) {
+; CHECK-LABEL: @ne_umin3(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 [[X]], %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ne i32 [[X]], [[SEL]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp ult i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp ne i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; Commute min operands.
+
+define i1 @ne_umin4(i32 %a, i32 %y) {
+; CHECK-LABEL: @ne_umin4(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ugt i32 [[X]], %y
+; CHECK-NEXT:    ret i1 [[CMP1]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp ult i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp ne i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; umin(X, Y) < X --> X > Y
+
+define i1 @ult_umin1(i32 %x, i32 %y) {
+; CHECK-LABEL: @ult_umin1(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 %x, %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %x, i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i32 [[SEL]], %x
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = icmp ult i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp ult i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Commute min operands.
+
+define i1 @ult_umin2(i32 %x, i32 %y) {
+; CHECK-LABEL: @ult_umin2(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 %y, %x
+; CHECK-NEXT:    ret i1 [[CMP1]]
+;
+  %cmp1 = icmp ult i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp ult i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Disguise the icmp predicate by commuting the min op to the RHS.
+
+define i1 @ult_umin3(i32 %a, i32 %y) {
+; CHECK-LABEL: @ult_umin3(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i32 [[X]], %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ugt i32 [[X]], [[SEL]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp ult i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp ugt i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; Commute min operands.
+
+define i1 @ult_umin4(i32 %a, i32 %y) {
+; CHECK-LABEL: @ult_umin4(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ugt i32 [[X]], %y
+; CHECK-NEXT:    ret i1 [[CMP1]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp ult i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp ugt i32 %x, %sel
+  ret i1 %cmp2
+}
+