[llvm-commits] [llvm] r164383 - in /llvm/trunk: lib/Transforms/Scalar/LoopIdiomRecognize.cpp test/Transforms/LoopIdiom/non-canonical-loop.ll

Benjamin Kramer benny.kra at googlemail.com
Fri Sep 21 10:27:23 PDT 2012


Author: d0k
Date: Fri Sep 21 12:27:23 2012
New Revision: 164383

URL: http://llvm.org/viewvc/llvm-project?rev=164383&view=rev
Log:
LoopIdiom: Give up when the loop is not in canonical form.

We rely on it when doing the transforms. This can happen when there is an
indirectbr in  the loop.

Fixes PR13892.

Added:
    llvm/trunk/test/Transforms/LoopIdiom/non-canonical-loop.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp?rev=164383&r1=164382&r2=164383&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp Fri Sep 21 12:27:23 2012
@@ -175,6 +175,11 @@
 bool LoopIdiomRecognize::runOnLoop(Loop *L, LPPassManager &LPM) {
   CurLoop = L;
 
+  // If the loop could not be converted to canonical form, it must have an
+  // indirectbr in it, just give up.
+  if (!L->getLoopPreheader())
+    return false;
+
   // Disable loop idiom recognition if the function's name is a common idiom.
   StringRef Name = L->getHeader()->getParent()->getName();
   if (Name == "memset" || Name == "memcpy")

Added: llvm/trunk/test/Transforms/LoopIdiom/non-canonical-loop.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopIdiom/non-canonical-loop.ll?rev=164383&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopIdiom/non-canonical-loop.ll (added)
+++ llvm/trunk/test/Transforms/LoopIdiom/non-canonical-loop.ll Fri Sep 21 12:27:23 2012
@@ -0,0 +1,34 @@
+; RUN: opt -S -loop-idiom < %s
+; Don't crash
+; PR13892
+
+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-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @test(i32* %currMB) nounwind uwtable {
+entry:
+  br i1 undef, label %start.exit, label %if.then.i
+
+if.then.i:                                        ; preds = %entry
+  unreachable
+
+start.exit:                       ; preds = %entry
+  indirectbr i8* undef, [label %0, label %for.bodyprime]
+
+; <label>:0                                       ; preds = %start.exit
+  unreachable
+
+for.bodyprime:                                    ; preds = %for.bodyprime, %start.exit
+  %i.057375 = phi i32 [ 0, %start.exit ], [ %1, %for.bodyprime ]
+  %arrayidx8prime = getelementptr inbounds i32* %currMB, i32 %i.057375
+  store i32 0, i32* %arrayidx8prime, align 4
+  %1 = add i32 %i.057375, 1
+  %cmp5prime = icmp slt i32 %1, 4
+  br i1 %cmp5prime, label %for.bodyprime, label %for.endprime
+
+for.endprime:                                     ; preds = %for.bodyprime
+  br label %for.body23prime
+
+for.body23prime:                                  ; preds = %for.body23prime, %for.endprime
+  br label %for.body23prime
+}





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