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| author | Wojciech Matyjewicz <wmatyjewicz@fastmail.fm> | 2008-02-12 15:09:36 +0000 |
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| committer | Wojciech Matyjewicz <wmatyjewicz@fastmail.fm> | 2008-02-12 15:09:36 +0000 |
| commit | a5718fc3ad7af8dc39f557e55881e365d56c550f (patch) | |
| tree | 80946930e84cc1b0228e8ab9081da9fe304e68e5 /test/Analysis | |
| parent | 350307faa8002cd91c610d0dcd98f7b443b4a889 (diff) | |
| download | external_llvm-a5718fc3ad7af8dc39f557e55881e365d56c550f.zip external_llvm-a5718fc3ad7af8dc39f557e55881e365d56c550f.tar.gz external_llvm-a5718fc3ad7af8dc39f557e55881e365d56c550f.tar.bz2 | |
Fix PR2002. Suppose n is the initial value for the induction
variable (with step 1) and m is its final value. Then, the correct trip
count is SMAX(m,n)-n. Previously, we used SMAX(0,m-n), but m-n may
overflow and can't in general be interpreted as signed.
Patch by Nick Lewycky.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47007 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Analysis')
| -rw-r--r-- | test/Analysis/ScalarEvolution/2008-02-12-SMAXTripCount.ll | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/test/Analysis/ScalarEvolution/2008-02-12-SMAXTripCount.ll b/test/Analysis/ScalarEvolution/2008-02-12-SMAXTripCount.ll new file mode 100644 index 0000000..292ea99 --- /dev/null +++ b/test/Analysis/ScalarEvolution/2008-02-12-SMAXTripCount.ll @@ -0,0 +1,16 @@ +; RUN: llvm-as < %s | opt -scalar-evolution -analyze | grep {Loop loop: ( 100 + ( -100 smax %n)) iterations!} +; PR2002 + +define void @foo(i8 %n) { +entry: + br label %loop +loop: + %i = phi i8 [ -100, %entry ], [ %i.inc, %next ] + %cond = icmp slt i8 %i, %n + br i1 %cond, label %next, label %return +next: + %i.inc = add i8 %i, 1 + br label %loop +return: + ret void +} |