Fix ScalarEvolution's tripcount computation for chains of loops

where each loop's induction variable's start value is the exit
value of a preceding loop.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107224 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 64 insertions, 2 deletions

diff --git a/test/Transforms/IndVarSimplify/tripcount_compute.ll b/test/Transforms/IndVarSimplify/tripcount_compute.ll
index 6eaa4c5..8835b96 100644
--- a/test/Transforms/IndVarSimplify/tripcount_compute.ll
+++ b/test/Transforms/IndVarSimplify/tripcount_compute.ll
@@ -1,9 +1,12 @@
+; RUN: opt < %s -indvars -S | FileCheck %s
+
 ; These tests ensure that we can compute the trip count of various forms of
 ; loops.  If the trip count of the loop is computable, then we will know what
 ; the exit value of the loop will be for some value, allowing us to substitute
 ; it directly into users outside of the loop, making the loop dead.
-;
-; RUN: opt < %s -indvars -loop-deletion -simplifycfg -S | not grep br
+
+; CHECK: @linear_setne
+; CHECK: ret i32 100
 
 define i32 @linear_setne() {
 entry:
@@ -19,6 +22,9 @@ loopexit:		; preds = %loop
 	ret i32 %i
 }
 
+; CHECK: @linear_setne_2
+; CHECK: ret i32 100
+
 define i32 @linear_setne_2() {
 entry:
 	br label %loop
@@ -33,6 +39,9 @@ loopexit:		; preds = %loop
 	ret i32 %i
 }
 
+; CHECK: @linear_setne_overflow
+; CHECK: ret i32 0
+
 define i32 @linear_setne_overflow() {
 entry:
 	br label %loop
@@ -47,6 +56,9 @@ loopexit:		; preds = %loop
 	ret i32 %i
 }
 
+; CHECK: @linear_setlt
+; CHECK: ret i32 100
+
 define i32 @linear_setlt() {
 entry:
 	br label %loop
@@ -61,6 +73,9 @@ loopexit:		; preds = %loop
 	ret i32 %i
 }
 
+; CHECK: @quadratic_setlt
+; CHECK: ret i32 34
+
 define i32 @quadratic_setlt() {
 entry:
 	br label %loop
@@ -76,6 +91,9 @@ loopexit:		; preds = %loop
 	ret i32 %i
 }
 
+; CHECK: @chained
+; CHECK: ret i32 200
+
 define i32 @chained() {
 entry:
 	br label %loop
@@ -98,3 +116,47 @@ loop2:		; preds = %loop2, %loopexit
 loopexit2:		; preds = %loop2
 	ret i32 %j
 }
+
+; CHECK: @chained4
+; CHECK: ret i32 400
+
+define i32 @chained4() {
+entry:
+  br label %loop
+
+loop:                                             ; preds = %loop, %entry
+  %i = phi i32 [ 0, %entry ], [ %i.next, %loop ]  ; <i32> [#uses=3]
+  %i.next = add i32 %i, 1                         ; <i32> [#uses=1]
+  %c = icmp ne i32 %i.next, 100                   ; <i1> [#uses=1]
+  br i1 %c, label %loop, label %loopexit
+
+loopexit:                                         ; preds = %loop
+  br label %loop2
+
+loop2:                                            ; preds = %loop2, %loopexit
+  %j = phi i32 [ %i.next, %loopexit ], [ %j.next, %loop2 ] ; <i32> [#uses=3]
+  %j.next = add i32 %j, 1                         ; <i32> [#uses=1]
+  %c2 = icmp ne i32 %j.next, 200                  ; <i1> [#uses=1]
+  br i1 %c2, label %loop2, label %loopexit2
+
+loopexit2:                                        ; preds = %loop
+  br label %loop8
+
+loop8:                                            ; preds = %loop2, %loopexit
+  %k = phi i32 [ %j.next, %loopexit2 ], [ %k.next, %loop8 ] ; <i32> [#uses=3]
+  %k.next = add i32 %k, 1                         ; <i32> [#uses=1]
+  %c8 = icmp ne i32 %k.next, 300                  ; <i1> [#uses=1]
+  br i1 %c8, label %loop8, label %loopexit8
+
+loopexit8:                                        ; preds = %loop2
+  br label %loop9
+
+loop9:                                            ; preds = %loop2, %loopexit
+  %l = phi i32 [ %k.next, %loopexit8 ], [ %l.next, %loop9 ] ; <i32> [#uses=3]
+  %l.next = add i32 %l, 1                         ; <i32> [#uses=1]
+  %c9 = icmp ne i32 %l.next, 400                  ; <i1> [#uses=1]
+  br i1 %c9, label %loop9, label %loopexit9
+
+loopexit9:                                        ; preds = %loop2
+  ret i32 %l.next
+}