Author: nicholas
Date: Mon Aug 6 13:33:46 2007
New Revision: 40866
URL: http://llvm.org/viewvc/llvm-project?rev=40866&view=rev
Log:
Don't assume it's safe to transform a loop just because it's dominated by any
comparison. Fixes bug 1598.
Added:
llvm/trunk/test/Analysis/ScalarEvolution/2007-09-06-MisinterpretBranch.ll
Modified:
llvm/trunk/lib/Analysis/ScalarEvolution.cpp
Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=40866&r1=40865&r2=40866&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Mon Aug 6 13:33:46 2007
@@ -2387,7 +2387,7 @@
return UnknownValue; // Not a comparison against 'n-1'.
}
else return UnknownValue;
- } else if (Cond == ICmpInst::ICMP_ULT)
+ } else
return UnknownValue;
// cerr << "Computed Loop Trip Count as: "
Added: llvm/trunk/test/Analysis/ScalarEvolution/2007-09-06-MisinterpretBranch.ll
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/2007-09-06-MisinterpretBranch.ll?rev=40866&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/2007-09-06-MisinterpretBranch.ll
(added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/2007-09-06-MisinterpretBranch.ll
Mon Aug 6 13:33:46 2007
@@ -0,0 +1,18 @@
+; RUN: llvm-as < %s | opt -indvars -adce -simplifycfg | llvm-dis | grep "icmp
s"
+; PR1598
+
+define i32 @f(i32 %a, i32 %b, i32 %x, i32 %y) {
+entry:
+ %tmp3 = icmp eq i32 %a, %b ; <i1> [#uses=1]
+ br i1 %tmp3, label %return, label %bb
+
+bb: ; preds = %bb, %entry
+ %x_addr.0 = phi i32 [ %tmp6, %bb ], [ %x, %entry ] ; <i32>
[#uses=1]
+ %tmp6 = add i32 %x_addr.0, 1 ; <i32> [#uses=3]
+ %tmp9 = icmp slt i32 %tmp6, %y ; <i1> [#uses=1]
+ br i1 %tmp9, label %bb, label %return
+
+return: ; preds = %bb, %entry
+ %x_addr.1 = phi i32 [ %x, %entry ], [ %tmp6, %bb ] ; <i32>
[#uses=1]
+ ret i32 %x_addr.1
+}
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