Don't assume it's safe to transform a loop just because it's dominated by any
comparison. Fixes bug 1598. llvm-svn: 40866
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@ -2387,7 +2387,7 @@ HowManyLessThans(SCEV *LHS, SCEV *RHS, const Loop *L) {
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return UnknownValue; // Not a comparison against 'n-1'.
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return UnknownValue; // Not a comparison against 'n-1'.
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}
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}
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else return UnknownValue;
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else return UnknownValue;
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} else if (Cond == ICmpInst::ICMP_ULT)
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} else
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return UnknownValue;
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return UnknownValue;
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// cerr << "Computed Loop Trip Count as: "
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// cerr << "Computed Loop Trip Count as: "
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@ -0,0 +1,18 @@
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; RUN: llvm-as < %s | opt -indvars -adce -simplifycfg | llvm-dis | grep "icmp s"
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; PR1598
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define i32 @f(i32 %a, i32 %b, i32 %x, i32 %y) {
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entry:
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%tmp3 = icmp eq i32 %a, %b ; <i1> [#uses=1]
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br i1 %tmp3, label %return, label %bb
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bb: ; preds = %bb, %entry
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%x_addr.0 = phi i32 [ %tmp6, %bb ], [ %x, %entry ] ; <i32> [#uses=1]
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%tmp6 = add i32 %x_addr.0, 1 ; <i32> [#uses=3]
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%tmp9 = icmp slt i32 %tmp6, %y ; <i1> [#uses=1]
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br i1 %tmp9, label %bb, label %return
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return: ; preds = %bb, %entry
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%x_addr.1 = phi i32 [ %x, %entry ], [ %tmp6, %bb ] ; <i32> [#uses=1]
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ret i32 %x_addr.1
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}
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