[InstCombine] add tests for smax+icmp; NFC

llvm-svn: 289151

diff --git a/llvm/test/Transforms/InstCombine/smax-icmp.ll b/llvm/test/Transforms/InstCombine/smax-icmp.ll
new file mode 100644 (file)
index 0000000..1462a96
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/smax-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 an smax feeding a signed or equality icmp that shares an
+; operand with the smax, the compare should always be folded.
+; Test all 4 foldable predicates (eq,ne,sgt,sle) * 4 commutation
+; possibilities for each predicate. Note that folds to true/false
+; (predicate = sge/slt) or folds to an existing instruction should be
+; handled by InstSimplify.
+
+; smax(X, Y) == X --> X >= Y
+
+define i1 @eq_smax1(i32 %x, i32 %y) {
+; CHECK-LABEL: @eq_smax1(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt 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 sgt i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp eq i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Commute max operands.
+
+define i1 @eq_smax2(i32 %x, i32 %y) {
+; CHECK-LABEL: @eq_smax2(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt 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 sgt 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 max op to the RHS.
+
+define i1 @eq_smax3(i32 %a, i32 %y) {
+; CHECK-LABEL: @eq_smax3(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt 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 sgt i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp eq i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; Commute max operands.
+
+define i1 @eq_smax4(i32 %a, i32 %y) {
+; CHECK-LABEL: @eq_smax4(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp slt 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 sgt i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp eq i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; smax(X, Y) <= X --> X >= Y
+
+define i1 @sle_smax1(i32 %x, i32 %y) {
+; CHECK-LABEL: @sle_smax1(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 %x, %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %x, i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sle i32 [[SEL]], %x
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = icmp sgt i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp sle i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Commute max operands.
+
+define i1 @sle_smax2(i32 %x, i32 %y) {
+; CHECK-LABEL: @sle_smax2(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 %y, %x
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %y, i32 %x
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sle i32 [[SEL]], %x
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = icmp sgt i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp sle i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Disguise the icmp predicate by commuting the max op to the RHS.
+
+define i1 @sle_smax3(i32 %a, i32 %y) {
+; CHECK-LABEL: @sle_smax3(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[X]], %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sge i32 [[X]], [[SEL]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp sgt i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp sge i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; Commute max operands.
+
+define i1 @sle_smax4(i32 %a, i32 %y) {
+; CHECK-LABEL: @sle_smax4(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp slt i32 [[X]], %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %y, i32 [[X]]
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sge i32 [[X]], [[SEL]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp sgt i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp sge i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; smax(X, Y) != X --> X < Y
+
+define i1 @ne_smax1(i32 %x, i32 %y) {
+; CHECK-LABEL: @ne_smax1(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt 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 sgt i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp ne i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Commute max operands.
+
+define i1 @ne_smax2(i32 %x, i32 %y) {
+; CHECK-LABEL: @ne_smax2(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 %y, %x
+; CHECK-NEXT:    ret i1 [[CMP1]]
+;
+  %cmp1 = icmp sgt 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 max op to the RHS.
+
+define i1 @ne_smax3(i32 %a, i32 %y) {
+; CHECK-LABEL: @ne_smax3(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt 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 sgt i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp ne i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; Commute max operands.
+
+define i1 @ne_smax4(i32 %a, i32 %y) {
+; CHECK-LABEL: @ne_smax4(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp slt i32 [[X]], %y
+; CHECK-NEXT:    ret i1 [[CMP1]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp sgt i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp ne i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; smax(X, Y) > X --> X < Y
+
+define i1 @sgt_smax1(i32 %x, i32 %y) {
+; CHECK-LABEL: @sgt_smax1(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 %x, %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 %x, i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp sgt i32 [[SEL]], %x
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = icmp sgt i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp sgt i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Commute max operands.
+
+define i1 @sgt_smax2(i32 %x, i32 %y) {
+; CHECK-LABEL: @sgt_smax2(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 %y, %x
+; CHECK-NEXT:    ret i1 [[CMP1]]
+;
+  %cmp1 = icmp sgt i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp sgt i32 %sel, %x
+  ret i1 %cmp2
+}
+
+; Disguise the icmp predicate by commuting the max op to the RHS.
+
+define i1 @sgt_smax3(i32 %a, i32 %y) {
+; CHECK-LABEL: @sgt_smax3(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[X]], %y
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], i32 [[X]], i32 %y
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp slt i32 [[X]], [[SEL]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp sgt i32 %x, %y
+  %sel = select i1 %cmp1, i32 %x, i32 %y
+  %cmp2 = icmp slt i32 %x, %sel
+  ret i1 %cmp2
+}
+
+; Commute max operands.
+
+define i1 @sgt_smax4(i32 %a, i32 %y) {
+; CHECK-LABEL: @sgt_smax4(
+; CHECK-NEXT:    [[X:%.*]] = add i32 %a, 3
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp slt i32 [[X]], %y
+; CHECK-NEXT:    ret i1 [[CMP1]]
+;
+  %x = add i32 %a, 3 ; thwart complexity-based canonicalization
+  %cmp1 = icmp sgt i32 %y, %x
+  %sel = select i1 %cmp1, i32 %y, i32 %x
+  %cmp2 = icmp slt i32 %x, %sel
+  ret i1 %cmp2
+}
+