llvm-6502/test/Analysis/ScalarEvolution/trip-count11.ll
Duncan Sands f8a9eb1fa6 Restore commits 142790 and 142843 - they weren't breaking the build
bots.  Original commit messages:
- Reapply r142781 with fix. Original message:

  Enhance SCEV's brute force loop analysis to handle multiple PHI nodes in the
  loop header when computing the trip count.

  With this, we now constant evaluate:
    struct ListNode { const struct ListNode *next; int i; };
    static const struct ListNode node1 = {0, 1};
    static const struct ListNode node2 = {&node1, 2};
    static const struct ListNode node3 = {&node2, 3};
    int test() {
      int sum = 0;
      for (const struct ListNode *n = &node3; n != 0; n = n->next)
        sum += n->i;
      return sum;
    }

- Now that we look at all the header PHIs, we need to consider all the header PHIs
  when deciding that the loop has stopped evolving. Fixes miscompile in the gcc
  torture testsuite!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142919 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-25 12:28:52 +00:00

30 lines
1.1 KiB
LLVM

; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@foo.a = internal constant [8 x i32] [i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7], align 16
define i32 @foo() nounwind uwtable noinline {
entry:
br label %for.cond
for.cond: ; preds = %for.inc, %entry
%sum.0 = phi i32 [ 0, %entry ], [ %add, %for.inc ]
; CHECK: --> %sum.0 Exits: 28
%i.0 = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
%cmp = icmp ult i32 %i.0, 8
br i1 %cmp, label %for.inc, label %for.end
for.inc: ; preds = %for.cond
%idxprom = sext i32 %i.0 to i64
%arrayidx = getelementptr inbounds [8 x i32]* @foo.a, i64 0, i64 %idxprom
%0 = load i32* %arrayidx, align 4
%add = add nsw i32 %sum.0, %0
%inc = add nsw i32 %i.0, 1
br label %for.cond
for.end: ; preds = %for.cond
ret i32 %sum.0
}