1; RUN: opt < %s -indvars -S | FileCheck %s 2 3; This is regression test for the bug in ScalarEvolution::isKnownPredicate. 4; It does not check whether SCEV is available at loop entry before invoking 5; and utility function isLoopEntryGuardedByCond and that leads to miscompile. 6 7target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128-ni:1" 8target triple = "x86_64-unknown-linux-gnu" 9 10declare void @foo(i64) 11declare void @bar(i32) 12 13define void @test(i8* %arr) { 14entry: 15 br label %outer_header 16 17outer_header: 18 %i = phi i32 [40, %entry], [%i.next, %outer_latch] 19 %i.64 = sext i32 %i to i64 20 br label %inner_header 21 22inner_header: 23 %j = phi i32 [27, %outer_header], [%j.next, %inner_backedge] 24 %j1 = zext i32 %j to i64 25; The next 4 lines are required for avoid widening of %j and 26; SCEV at %cmp would not be AddRec. 27 %gep = getelementptr inbounds i8, i8* %arr, i64 %j1 28 %ld = load i8, i8* %gep 29 %ec = icmp eq i8 %ld, 0 30 br i1 %ec, label %return, label %inner_backedge 31 32inner_backedge: 33 %cmp = icmp ult i32 %j, %i 34 %s = select i1 %cmp, i32 %i, i32 %j 35; Select should not be simplified because if 36; %i == 26 and %j == 27, %s should be equal to %j. 37; In case of a bug the instruction is simplified to 38; %s = select i1 true, i32 %0, i32 %j 39; CHECK-NOT: %s = select i1 true 40 call void @bar(i32 %s) 41 %j.next = add nsw i32 %j, -2 42 %cond = icmp ult i32 %j, 3 43 br i1 %cond, label %outer_latch, label %inner_header 44 45outer_latch: 46 %i.next = add i32 %i, -1 47 %cond2 = icmp sgt i32 %i.next, 13 48; This line is just for forcing widening of %i 49 call void @foo(i64 %i.64) 50 br i1 %cond2, label %outer_header, label %return 51 52return: 53 ret void 54} 55