From: Owen Anderson <resistor@mac.com>
Date: Thu, 16 Sep 2010 18:28:33 +0000 (+0000)
Subject: It is possible, under specific circumstances involving ptrtoint ConstantExpr's, for... 
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=c2ce21ad51590377b572a572243e373f7a7b9fb4

It is possible, under specific circumstances involving ptrtoint ConstantExpr's, for LVI to end up trying to merge
a Constant into a ConstantRange.  Handle this conservatively for now, rather than asserting.  The testcase is
more complex that I would like, but the manifestation of the problem is sensitive to iteration orders and the state of the
LVI cache, and I have not been able to reproduce it with manually constructed or simplified cases.

Fixes PR8162.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114103 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/LazyValueInfo.cpp b/lib/Analysis/LazyValueInfo.cpp
index 74267e045ae..0e024042f17 100644
--- a/lib/Analysis/LazyValueInfo.cpp
+++ b/lib/Analysis/LazyValueInfo.cpp
@@ -201,6 +201,7 @@ public:
           return markOverdefined();
         return markNotConstant(RHS.getNotConstant());
       } else if (isConstantRange()) {
+         // FIXME: This could be made more precise.
         return markOverdefined();
       }
       
@@ -223,9 +224,12 @@ public:
       return markConstantRange(RHS.getConstantRange());
     }
     
-    // RHS must be a constant, we must be undef, constant, or notconstant.
-    assert(!isConstantRange() &&
-           "Constant and ConstantRange cannot be merged.");
+    // RHS must be a constant, we must be constantrange, 
+    // undef, constant, or notconstant.
+    if (isConstantRange()) {
+      // FIXME: This could be made more precise.
+      return markOverdefined();
+    }
     
     if (isUndefined())
       return markConstant(RHS.getConstant());
diff --git a/test/Transforms/CorrelatedValuePropagation/2010-09-26-MergeConstantRange.ll b/test/Transforms/CorrelatedValuePropagation/2010-09-26-MergeConstantRange.ll
new file mode 100644
index 00000000000..bc4e921ccca
--- /dev/null
+++ b/test/Transforms/CorrelatedValuePropagation/2010-09-26-MergeConstantRange.ll
@@ -0,0 +1,84 @@
+; ModuleID = 'bugpoint-reduced-simplified.bc'
+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"
+target triple = "x86_64-apple-darwin11.0.0"
+
+%struct.S2 = type {}
+
+@g_128 = external global %struct.S2, align 1
+@g_106 = external global i16, align 2
+
+define void @int328(i16 signext %p_82) noreturn nounwind ssp {
+entry:
+  %tobool3 = icmp eq i16 %p_82, 0
+  br label %for.cond.outer
+
+for.cond.outer:                                   ; preds = %for.cond.loopexit, %entry
+  br label %for.cond
+
+for.cond.loopexit:                                ; preds = %bb.nph, %for.cond9.preheader
+  br label %for.cond.outer
+
+for.cond.loopexit4.us-lcssa:                      ; preds = %if.then
+  br label %for.cond.loopexit4
+
+for.cond.loopexit4:                               ; preds = %for.cond.loopexit4.us-lcssa.us, %for.cond.loopexit4.us-lcssa
+  br label %for.cond.backedge
+
+for.cond:                                         ; preds = %for.cond.backedge, %for.cond.outer
+  br i1 %tobool3, label %for.cond.split.us, label %for.cond.for.cond.split_crit_edge
+
+for.cond.for.cond.split_crit_edge:                ; preds = %for.cond
+  br label %lbl_133
+
+for.cond.split.us:                                ; preds = %for.cond
+  br label %lbl_133.us
+
+lbl_133.us:                                       ; preds = %lbl_134.us, %for.cond.split.us
+  br i1 undef, label %if.else14.us-lcssa.us, label %if.then.us
+
+lbl_134.us:                                       ; preds = %if.then.us
+  br i1 icmp eq (i16 ptrtoint (%struct.S2* @g_128 to i16), i16 0), label %for.cond9.preheader.us-lcssa.us, label %lbl_133.us
+
+if.then.us:                                       ; preds = %lbl_133.us
+  br i1 true, label %for.cond.loopexit4.us-lcssa.us, label %lbl_134.us
+
+if.else14.us-lcssa.us:                            ; preds = %lbl_133.us
+  br label %if.else14
+
+for.cond9.preheader.us-lcssa.us:                  ; preds = %lbl_134.us
+  br label %for.cond9.preheader
+
+for.cond.loopexit4.us-lcssa.us:                   ; preds = %if.then.us
+  br label %for.cond.loopexit4
+
+lbl_133:                                          ; preds = %lbl_134, %for.cond.for.cond.split_crit_edge
+  %l_109.0 = phi i16 [ 0, %for.cond.for.cond.split_crit_edge ], [ ptrtoint (%struct.S2* @g_128 to i16), %lbl_134 ]
+  %tobool = icmp eq i32 undef, 0
+  br i1 %tobool, label %if.else14.us-lcssa, label %if.then
+
+if.then:                                          ; preds = %lbl_133
+  br i1 false, label %for.cond.loopexit4.us-lcssa, label %lbl_134
+
+lbl_134:                                          ; preds = %if.then
+  br i1 icmp eq (i16 ptrtoint (%struct.S2* @g_128 to i16), i16 0), label %for.cond9.preheader.us-lcssa, label %lbl_133
+
+for.cond9.preheader.us-lcssa:                     ; preds = %lbl_134
+  br label %for.cond9.preheader
+
+for.cond9.preheader:                              ; preds = %for.cond9.preheader.us-lcssa, %for.cond9.preheader.us-lcssa.us
+  br i1 undef, label %bb.nph, label %for.cond.loopexit
+
+bb.nph:                                           ; preds = %for.cond9.preheader
+  br label %for.cond.loopexit
+
+if.else14.us-lcssa:                               ; preds = %lbl_133
+  br label %if.else14
+
+if.else14:                                        ; preds = %if.else14.us-lcssa, %if.else14.us-lcssa.us
+  %l_109.0.lcssa = phi i16 [ %l_109.0, %if.else14.us-lcssa ], [ 0, %if.else14.us-lcssa.us ]
+  store i16 undef, i16* @g_106, align 2
+  br label %for.cond.backedge
+
+for.cond.backedge:                                ; preds = %if.else14, %for.cond.loopexit4
+  br label %for.cond
+}