llvm-6502/test/Analysis/ScalarEvolution/2008-07-29-SMinExpr.ll
Dan Gohman 4d52c6d622 Optimize ScalarEvolution's SCEVComplexityCompare predicate: don't go
scrounging through SCEVUnknown contents and SCEVNAryExpr operands;
instead just do a simple deterministic comparison of the precomputed
hash data.

Also, since this is more precise, it eliminates the need for the slow
N^2 duplicate detection code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105540 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-07 19:06:13 +00:00

27 lines
808 B
LLVM

; RUN: opt < %s -analyze -scalar-evolution \
; RUN: -scalar-evolution-max-iterations=0 | FileCheck %s
; PR2607
define i32 @b(i32 %x, i32 %y) nounwind {
entry:
%cmp2 = icmp slt i32 %y, %x
%cond3 = select i1 %cmp2, i32 %y, i32 %x
%cmp54 = icmp slt i32 %cond3, -2147483632
br i1 %cmp54, label %forinc, label %afterfor
forinc: ; preds = %forinc, %entry
%j.01 = phi i32 [ %dec, %forinc ], [ -2147483632, %entry ]
%dec = add i32 %j.01, -1
%cmp = icmp slt i32 %y, %x
%cond = select i1 %cmp, i32 %y, i32 %x
%cmp5 = icmp sgt i32 %dec, %cond
br i1 %cmp5, label %forinc, label %afterfor
afterfor: ; preds = %forinc, %entry
%j.0.lcssa = phi i32 [ -2147483632, %entry ], [ %dec, %forinc ]
ret i32 %j.0.lcssa
}
; CHECK: backedge-taken count is (-2147483632 + ((-1 + (-1 * %y)) smax (-1 + (-1 * %x))))