[CVP] Add additional tests for clamp patterns (NFC)

These are the same as the existing tests, but using different
predicates that are not handled by the current code.

Author: nikic

llvm/test/Transforms/CorrelatedValuePropagation/basic.ll

@@ -578,6 +578,62 @@ out:
   ret i1 false
 }
 
+define i1 @clamp_low3(i32 %a) {
+; CHECK-LABEL: @clamp_low3(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sge i32 [[A:%.*]], 5
+; CHECK-NEXT:    br i1 [[CMP]], label [[A_GUARD:%.*]], label [[OUT:%.*]]
+; CHECK:       a_guard:
+; CHECK-NEXT:    [[SEL_CMP:%.*]] = icmp sgt i32 [[A]], 5
+; CHECK-NEXT:    [[ADD:%.*]] = add nsw i32 [[A]], -1
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[SEL_CMP]], i32 [[ADD]], i32 5
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i32 [[SEL]], 4
+; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK:       out:
+; CHECK-NEXT:    ret i1 false
+;
+entry:
+  %cmp = icmp sge i32 %a, 5
+  br i1 %cmp, label %a_guard, label %out
+
+a_guard:
+  %sel_cmp = icmp sgt i32 %a, 5
+  %add = add i32 %a, -1
+  %sel = select i1 %sel_cmp, i32 %add, i32 5
+  %res = icmp eq i32 %sel, 4
+  ret i1 %res
+out:
+  ret i1 false
+}
+
+define i1 @clamp_low4(i32 %a) {
+; CHECK-LABEL: @clamp_low4(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sge i32 [[A:%.*]], 5
+; CHECK-NEXT:    br i1 [[CMP]], label [[A_GUARD:%.*]], label [[OUT:%.*]]
+; CHECK:       a_guard:
+; CHECK-NEXT:    [[SEL_CMP:%.*]] = icmp sle i32 [[A]], 5
+; CHECK-NEXT:    [[ADD:%.*]] = add nsw i32 [[A]], -1
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[SEL_CMP]], i32 5, i32 [[ADD]]
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i32 [[SEL]], 4
+; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK:       out:
+; CHECK-NEXT:    ret i1 false
+;
+entry:
+  %cmp = icmp sge i32 %a, 5
+  br i1 %cmp, label %a_guard, label %out
+
+a_guard:
+  %sel_cmp = icmp sle i32 %a, 5
+  %add = add i32 %a, -1
+  %sel = select i1 %sel_cmp, i32 5, i32 %add
+  %res = icmp eq i32 %sel, 4
+  ret i1 %res
+out:
+  ret i1 false
+}
+
 define i1 @clamp_high1(i32 %a) {
 ; CHECK-LABEL: @clamp_high1(
 ; CHECK-NEXT:  entry:
@@ -632,13 +688,69 @@ out:
   ret i1 false
 }
 
-; Just showing arbitrary constants work, not really a clamp
 define i1 @clamp_high3(i32 %a) {
 ; CHECK-LABEL: @clamp_high3(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp sle i32 [[A:%.*]], 5
 ; CHECK-NEXT:    br i1 [[CMP]], label [[A_GUARD:%.*]], label [[OUT:%.*]]
 ; CHECK:       a_guard:
+; CHECK-NEXT:    [[SEL_CMP:%.*]] = icmp slt i32 [[A]], 5
+; CHECK-NEXT:    [[ADD:%.*]] = add nsw i32 [[A]], 1
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[SEL_CMP]], i32 [[ADD]], i32 5
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i32 [[SEL]], 6
+; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK:       out:
+; CHECK-NEXT:    ret i1 false
+;
+entry:
+  %cmp = icmp sle i32 %a, 5
+  br i1 %cmp, label %a_guard, label %out
+
+a_guard:
+  %sel_cmp = icmp slt i32 %a, 5
+  %add = add i32 %a, 1
+  %sel = select i1 %sel_cmp, i32 %add, i32 5
+  %res = icmp eq i32 %sel, 6
+  ret i1 %res
+out:
+  ret i1 false
+}
+
+define i1 @clamp_high4(i32 %a) {
+; CHECK-LABEL: @clamp_high4(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sle i32 [[A:%.*]], 5
+; CHECK-NEXT:    br i1 [[CMP]], label [[A_GUARD:%.*]], label [[OUT:%.*]]
+; CHECK:       a_guard:
+; CHECK-NEXT:    [[SEL_CMP:%.*]] = icmp sge i32 [[A]], 5
+; CHECK-NEXT:    [[ADD:%.*]] = add nsw i32 [[A]], 1
+; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[SEL_CMP]], i32 5, i32 [[ADD]]
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i32 [[SEL]], 6
+; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK:       out:
+; CHECK-NEXT:    ret i1 false
+;
+entry:
+  %cmp = icmp sle i32 %a, 5
+  br i1 %cmp, label %a_guard, label %out
+
+a_guard:
+  %sel_cmp = icmp sge i32 %a, 5
+  %add = add i32 %a, 1
+  %sel = select i1 %sel_cmp, i32 5, i32 %add
+  %res = icmp eq i32 %sel, 6
+  ret i1 %res
+out:
+  ret i1 false
+}
+
+; Just showing arbitrary constants work, not really a clamp
+define i1 @not_clamp_high(i32 %a) {
+; CHECK-LABEL: @not_clamp_high(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sle i32 [[A:%.*]], 5
+; CHECK-NEXT:    br i1 [[CMP]], label [[A_GUARD:%.*]], label [[OUT:%.*]]
+; CHECK:       a_guard:
 ; CHECK-NEXT:    [[SEL_CMP:%.*]] = icmp ne i32 [[A]], 5
 ; CHECK-NEXT:    [[ADD:%.*]] = add nsw i32 [[A]], 100
 ; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[SEL_CMP]], i32 [[ADD]], i32 5