[Tests] Add tests to highlight sibling loop optimization order issue for exit rewriting

The issue addressed in r363180 is more broadly relevant.  For the moment, we don't actually get any of these cases because we a) restrict SCEV formation due to SCEExpander needing to preserve LCSSA, and b) don't iterate between loops.

llvm-svn: 363192

1 files changed, 151 insertions, 2 deletions

diff --git a/llvm/test/Transforms/IndVarSimplify/pr39673.ll b/llvm/test/Transforms/IndVarSimplify/pr39673.ll
index 422281a007a..f11c4ab3ad0 100644
--- a/llvm/test/Transforms/IndVarSimplify/pr39673.ll
+++ b/llvm/test/Transforms/IndVarSimplify/pr39673.ll
@@ -1,8 +1,8 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -S -indvars < %s | FileCheck %s
 
-define i16 @test() {
-; CHECK-LABEL: @test(
+define i16 @constant() {
+; CHECK-LABEL: @constant(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[LOOP1:%.*]]
 ; CHECK:       loop1:
@@ -52,4 +52,153 @@ loop2.end:                                       ; preds = %loop2
   ret i16 %k2.add.lcssa
 }
 
+define i16 @dom_argument(i16 %arg1, i16 %arg2) {
+; CHECK-LABEL: @dom_argument(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP1:%.*]]
+; CHECK:       loop1:
+; CHECK-NEXT:    [[L1:%.*]] = phi i16 [ 0, [[ENTRY:%.*]] ], [ [[L1_ADD:%.*]], [[LOOP1]] ]
+; CHECK-NEXT:    [[SELECTOR:%.*]] = phi i16 [ [[ARG1:%.*]], [[ENTRY]] ], [ [[ARG2:%.*]], [[LOOP1]] ]
+; CHECK-NEXT:    [[L1_ADD]] = add nuw nsw i16 [[L1]], 1
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i16 [[L1_ADD]], 2
+; CHECK-NEXT:    br i1 [[CMP1]], label [[LOOP1]], label [[LOOP2_PREHEADER:%.*]]
+; CHECK:       loop2.preheader:
+; CHECK-NEXT:    [[K1_ADD_LCSSA:%.*]] = phi i16 [ [[SELECTOR]], [[LOOP1]] ]
+; CHECK-NEXT:    br label [[LOOP2:%.*]]
+; CHECK:       loop2:
+; CHECK-NEXT:    [[K2:%.*]] = phi i16 [ [[K2_ADD:%.*]], [[LOOP2]] ], [ [[K1_ADD_LCSSA]], [[LOOP2_PREHEADER]] ]
+; CHECK-NEXT:    [[L2:%.*]] = phi i16 [ [[L2_ADD:%.*]], [[LOOP2]] ], [ 0, [[LOOP2_PREHEADER]] ]
+; CHECK-NEXT:    [[L2_ADD]] = add nuw nsw i16 [[L2]], 1
+; CHECK-NEXT:    tail call void @foo(i16 [[K2]])
+; CHECK-NEXT:    [[K2_ADD]] = add nuw nsw i16 [[K2]], 1
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i16 [[L2_ADD]], 2
+; CHECK-NEXT:    br i1 [[CMP2]], label [[LOOP2]], label [[LOOP2_END:%.*]]
+; CHECK:       loop2.end:
+; CHECK-NEXT:    [[K2_ADD_LCSSA:%.*]] = phi i16 [ [[K2_ADD]], [[LOOP2]] ]
+; CHECK-NEXT:    ret i16 [[K2_ADD_LCSSA]]
+;
+entry:
+  br label %loop1
+
+loop1:                                           ; preds = %entry, %loop1
+  %k1 = phi i16 [ 100, %entry ], [ %k1.add, %loop1 ]
+  %l1 = phi i16 [ 0, %entry ], [ %l1.add, %loop1 ]
+  %selector = phi i16 [ %arg1, %entry ], [ %arg2, %loop1 ]
+  %k1.add = add nuw nsw i16 %k1, 1
+  %l1.add = add nuw nsw i16 %l1, 1
+  %cmp1 = icmp ult i16 %l1.add, 2
+  br i1 %cmp1, label %loop1, label %loop2.preheader
+
+loop2.preheader:                                 ; preds = %loop1
+  %k1.add.lcssa = phi i16 [ %selector, %loop1 ]
+  br label %loop2
+
+loop2:                                           ; preds = %loop2.preheader, %loop2
+  %k2 = phi i16 [ %k2.add, %loop2 ], [ %k1.add.lcssa, %loop2.preheader ]
+  %l2 = phi i16 [ %l2.add, %loop2 ], [ 0, %loop2.preheader ]
+  %l2.add = add nuw i16 %l2, 1
+  tail call void @foo(i16 %k2)
+  %k2.add = add nuw nsw i16 %k2, 1
+  %cmp2 = icmp ult i16 %l2.add, 2
+  br i1 %cmp2, label %loop2, label %loop2.end
+
+loop2.end:                                       ; preds = %loop2
+  %k2.add.lcssa = phi i16 [ %k2.add, %loop2 ]
+  ret i16 %k2.add.lcssa
+}
+
+define i16 @dummy_phi_outside_loop(i16 %arg) {
+; CHECK-LABEL: @dummy_phi_outside_loop(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP2_PREHEADER:%.*]]
+; CHECK:       loop2.preheader:
+; CHECK-NEXT:    [[DUMMY:%.*]] = phi i16 [ [[ARG:%.*]], [[ENTRY:%.*]] ]
+; CHECK-NEXT:    br label [[LOOP2:%.*]]
+; CHECK:       loop2:
+; CHECK-NEXT:    [[K2:%.*]] = phi i16 [ [[K2_ADD:%.*]], [[LOOP2]] ], [ [[DUMMY]], [[LOOP2_PREHEADER]] ]
+; CHECK-NEXT:    [[L2:%.*]] = phi i16 [ [[L2_ADD:%.*]], [[LOOP2]] ], [ 0, [[LOOP2_PREHEADER]] ]
+; CHECK-NEXT:    [[L2_ADD]] = add nuw nsw i16 [[L2]], 1
+; CHECK-NEXT:    tail call void @foo(i16 [[K2]])
+; CHECK-NEXT:    [[K2_ADD]] = add nuw nsw i16 [[K2]], 1
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i16 [[L2_ADD]], 2
+; CHECK-NEXT:    br i1 [[CMP2]], label [[LOOP2]], label [[LOOP2_END:%.*]]
+; CHECK:       loop2.end:
+; CHECK-NEXT:    [[K2_ADD_LCSSA:%.*]] = phi i16 [ [[K2_ADD]], [[LOOP2]] ]
+; CHECK-NEXT:    ret i16 [[K2_ADD_LCSSA]]
+;
+entry:
+  br label %loop2.preheader
+
+loop2.preheader:                                 ; preds = %loop1
+  %dummy = phi i16 [ %arg, %entry ]
+  br label %loop2
+
+loop2:                                           ; preds = %loop2.preheader, %loop2
+  %k2 = phi i16 [ %k2.add, %loop2 ], [ %dummy, %loop2.preheader ]
+  %l2 = phi i16 [ %l2.add, %loop2 ], [ 0, %loop2.preheader ]
+  %l2.add = add nuw i16 %l2, 1
+  tail call void @foo(i16 %k2)
+  %k2.add = add nuw nsw i16 %k2, 1
+  %cmp2 = icmp ult i16 %l2.add, 2
+  br i1 %cmp2, label %loop2, label %loop2.end
+
+loop2.end:                                       ; preds = %loop2
+  %k2.add.lcssa = phi i16 [ %k2.add, %loop2 ]
+  ret i16 %k2.add.lcssa
+}
+
+define i16 @neg_loop_carried(i16 %arg) {
+; CHECK-LABEL: @neg_loop_carried(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP1:%.*]]
+; CHECK:       loop1:
+; CHECK-NEXT:    [[L1:%.*]] = phi i16 [ 0, [[ENTRY:%.*]] ], [ [[L1_ADD:%.*]], [[LOOP1]] ]
+; CHECK-NEXT:    [[L1_ADD]] = add nuw nsw i16 [[L1]], 1
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i16 [[L1_ADD]], 2
+; CHECK-NEXT:    br i1 [[CMP1]], label [[LOOP1]], label [[LOOP2_PREHEADER:%.*]]
+; CHECK:       loop2.preheader:
+; CHECK-NEXT:    [[TMP0:%.*]] = add i16 [[ARG:%.*]], 2
+; CHECK-NEXT:    br label [[LOOP2:%.*]]
+; CHECK:       loop2:
+; CHECK-NEXT:    [[K2:%.*]] = phi i16 [ [[K2_ADD:%.*]], [[LOOP2]] ], [ [[TMP0]], [[LOOP2_PREHEADER]] ]
+; CHECK-NEXT:    [[L2:%.*]] = phi i16 [ [[L2_ADD:%.*]], [[LOOP2]] ], [ 0, [[LOOP2_PREHEADER]] ]
+; CHECK-NEXT:    [[L2_ADD]] = add nuw nsw i16 [[L2]], 1
+; CHECK-NEXT:    tail call void @foo(i16 [[K2]])
+; CHECK-NEXT:    [[K2_ADD]] = add nuw nsw i16 [[K2]], 1
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i16 [[L2_ADD]], 2
+; CHECK-NEXT:    br i1 [[CMP2]], label [[LOOP2]], label [[LOOP2_END:%.*]]
+; CHECK:       loop2.end:
+; CHECK-NEXT:    [[K2_ADD_LCSSA:%.*]] = phi i16 [ [[K2_ADD]], [[LOOP2]] ]
+; CHECK-NEXT:    ret i16 [[K2_ADD_LCSSA]]
+;
+entry:
+  br label %loop1
+
+loop1:                                           ; preds = %entry, %loop1
+  %k1 = phi i16 [ %arg, %entry ], [ %k1.add, %loop1 ]
+  %l1 = phi i16 [ 0, %entry ], [ %l1.add, %loop1 ]
+  %k1.add = add nuw nsw i16 %k1, 1
+  %l1.add = add nuw nsw i16 %l1, 1
+  %cmp1 = icmp ult i16 %l1.add, 2
+  br i1 %cmp1, label %loop1, label %loop2.preheader
+
+loop2.preheader:                                 ; preds = %loop1
+  %k1.add.lcssa = phi i16 [ %k1.add, %loop1 ]
+  br label %loop2
+
+loop2:                                           ; preds = %loop2.preheader, %loop2
+  %k2 = phi i16 [ %k2.add, %loop2 ], [ %k1.add.lcssa, %loop2.preheader ]
+  %l2 = phi i16 [ %l2.add, %loop2 ], [ 0, %loop2.preheader ]
+  %l2.add = add nuw i16 %l2, 1
+  tail call void @foo(i16 %k2)
+  %k2.add = add nuw nsw i16 %k2, 1
+  %cmp2 = icmp ult i16 %l2.add, 2
+  br i1 %cmp2, label %loop2, label %loop2.end
+
+loop2.end:                                       ; preds = %loop2
+  %k2.add.lcssa = phi i16 [ %k2.add, %loop2 ]
+  ret i16 %k2.add.lcssa
+}
+
+
 declare void @foo(i16)