llvm-6502/test/Analysis/ScalarEvolution/2008-02-12-SMAXTripCount.ll
Wojciech Matyjewicz 7b5b76835a 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
2008-02-12 15:09:36 +00:00

17 lines
366 B
LLVM

; 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
}