From 606199fb85d1c8407615e575b5e8bb5c71be27bd Mon Sep 17 00:00:00 2001 From: Duncan Sands Date: Tue, 8 Mar 2011 12:39:03 +0000 Subject: [PATCH] Fix PR9331. Simplified version of a patch by Jakub Staszak. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127243 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ValueTracking.cpp | 4 ++ test/Transforms/JumpThreading/pr9331.ll | 50 +++++++++++++++++++++++++ 2 files changed, 54 insertions(+) create mode 100644 test/Transforms/JumpThreading/pr9331.ll diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 231b95b618f..f05ad66b87d 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -610,6 +610,10 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, // Otherwise take the unions of the known bit sets of the operands, // taking conservative care to avoid excessive recursion. if (Depth < MaxDepth - 1 && !KnownZero && !KnownOne) { + // Skip if every incoming value references to ourself. + if (P->hasConstantValue() == P) + break; + KnownZero = APInt::getAllOnesValue(BitWidth); KnownOne = APInt::getAllOnesValue(BitWidth); for (unsigned i = 0, e = P->getNumIncomingValues(); i != e; ++i) { diff --git a/test/Transforms/JumpThreading/pr9331.ll b/test/Transforms/JumpThreading/pr9331.ll new file mode 100644 index 00000000000..4c06d526ca1 --- /dev/null +++ b/test/Transforms/JumpThreading/pr9331.ll @@ -0,0 +1,50 @@ +; RUN: opt -jump-threading -S < %s + +define void @func(i8 zeroext %p_44) nounwind { +entry: + br i1 false, label %for.cond2, label %if.end50 + +for.cond2: ; preds = %for.inc46, %lor.end, %entry + %p_44.addr.1 = phi i8 [ %p_44.addr.1, %lor.end ], [ %p_44, %entry ], [ %p_44.addr.1, %for.inc46 ] + br i1 undef, label %for.inc46, label %for.body5 + +for.body5: ; preds = %for.cond2 + br i1 undef, label %lbl_465, label %if.then9 + +if.then9: ; preds = %for.body5 + br label %return + +lbl_465: ; preds = %lbl_465, %for.body5 + %tobool19 = icmp eq i8 undef, 0 + br i1 %tobool19, label %if.end21, label %lbl_465 + +if.end21: ; preds = %lbl_465 + %conv23 = zext i8 %p_44.addr.1 to i64 + %xor = xor i64 %conv23, 1 + %tobool.i = icmp eq i64 %conv23, 0 + br i1 %tobool.i, label %cond.false.i, label %safe_mod_func_uint64_t_u_u.exit + +cond.false.i: ; preds = %if.end21 + %div.i = udiv i64 %xor, %conv23 + br label %safe_mod_func_uint64_t_u_u.exit + +safe_mod_func_uint64_t_u_u.exit: ; preds = %cond.false.i, %if.end21 + %cond.i = phi i64 [ %div.i, %cond.false.i ], [ %conv23, %if.end21 ] + %tobool28 = icmp eq i64 %cond.i, 0 + br i1 %tobool28, label %lor.rhs, label %lor.end + +lor.rhs: ; preds = %safe_mod_func_uint64_t_u_u.exit + br label %lor.end + +lor.end: ; preds = %lor.rhs, %safe_mod_func_uint64_t_u_u.exit + br label %for.cond2 + +for.inc46: ; preds = %for.cond2 + br label %for.cond2 + +if.end50: ; preds = %entry + br label %return + +return: ; preds = %if.end50, %if.then9 + ret void +}