LFTR should avoid a type mismatch with null pointer IVs.

Fixes rdar://10359193 Indvar LinearFunctionTestReplace assertion

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143183 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index 874a135110df0a50724669801cafa5862f33af66..dce7f87e2c26f9564dc36b4840dd9dc4d7a7e5ce 100644 (file)
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -1558,8 +1558,7 @@ LinearFunctionTestReplace(Loop *L,
   }
 
   // For unit stride, IVLimit = Start + BECount with 2's complement overflow.
-  // So for, non-zero start compute the IVLimit here.
-  bool isPtrIV = false;
+  // So for non-zero start compute the IVLimit here.
   Type *CmpTy = CntTy;
   const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(SE->getSCEV(IndVar));
   assert(AR && AR->getLoop() == L && AR->isAffine() && "bad loop counter");
@@ -1571,8 +1570,7 @@ LinearFunctionTestReplace(Loop *L,
     // Note that for without EnableIVRewrite, we never run SCEVExpander on a
     // pointer type, because we must preserve the existing GEPs. Instead we
     // directly generate a GEP later.
-    if (IVInit->getType()->isPointerTy()) {
-      isPtrIV = true;
+    if (CmpIndVar->getType()->isPointerTy()) {
       CmpTy = SE->getEffectiveSCEVType(IVInit->getType());
       IVLimit = SE->getTruncateOrSignExtend(IVLimit, CmpTy);
     }
@@ -1590,21 +1588,25 @@ LinearFunctionTestReplace(Loop *L,
 
   assert(SE->isLoopInvariant(IVLimit, L) &&
          "Computed iteration count is not loop invariant!");
+  assert( !IVLimit->getType()->isPointerTy() &&
+          "Should not expand pointer types" );
   Value *ExitCnt = Rewriter.expandCodeFor(IVLimit, CmpTy, BI);
 
   // Create a gep for IVInit + IVLimit from on an existing pointer base.
-  assert(isPtrIV == IndVar->getType()->isPointerTy() &&
-         "IndVar type must match IVInit type");
-  if (isPtrIV) {
-      Value *IVStart = IndVar->getIncomingValueForBlock(L->getLoopPreheader());
-      assert(AR->getStart() == SE->getSCEV(IVStart) && "bad loop counter");
-      assert(SE->getSizeOfExpr(
-               cast<PointerType>(IVStart->getType())->getElementType())->isOne()
-             && "unit stride pointer IV must be i8*");
-
-      Builder.SetInsertPoint(L->getLoopPreheader()->getTerminator());
-      ExitCnt = Builder.CreateGEP(IVStart, ExitCnt, "lftr.limit");
-      Builder.SetInsertPoint(BI);
+  //
+  // In the presence of null pointer values, the SCEV expression may be an
+  // integer type while the IV is a pointer type. Ensure that the compare
+  // operands are always the same type by checking the IV type here.
+  if (CmpIndVar->getType()->isPointerTy()) {
+    Value *IVStart = IndVar->getIncomingValueForBlock(L->getLoopPreheader());
+    assert(AR->getStart() == SE->getSCEV(IVStart) && "bad loop counter");
+    assert(SE->getSizeOfExpr(
+             cast<PointerType>(IVStart->getType())->getElementType())->isOne()
+           && "unit stride pointer IV must be i8*");
+
+    Builder.SetInsertPoint(L->getLoopPreheader()->getTerminator());
+    ExitCnt = Builder.CreateGEP(IVStart, ExitCnt, "lftr.limit");
+    Builder.SetInsertPoint(BI);
   }
 
   // Insert a new icmp_ne or icmp_eq instruction before the branch.

diff --git a/test/Transforms/IndVarSimplify/2011-10-27-lftrnull.ll b/test/Transforms/IndVarSimplify/2011-10-27-lftrnull.ll
new file mode 100644 (file)
index 0000000..76c90e0
--- /dev/null
+++ b/test/Transforms/IndVarSimplify/2011-10-27-lftrnull.ll
@@ -0,0 +1,59 @@
+; RUN: opt < %s -indvars -S | FileCheck %s
+; rdar://10359193: assert "IndVar type must match IVInit type"
+
+target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n32-S32"
+target triple = "thumbv7-apple-darwin"
+
+; CHECK: @test
+; CHECK: if.end.i126:
+; CHECK: %exitcond = icmp ne i8* %incdec.ptr.i, getelementptr (i8* null, i32 undef)
+define void @test() nounwind {
+entry:
+  br label %while.cond
+
+while.cond:
+  br i1 undef, label %while.end, label %while.body
+
+while.body:                                       ; preds = %while.cond
+  br i1 undef, label %if.then165, label %while.cond
+
+if.then165:                                       ; preds = %while.body
+  br i1 undef, label %while.cond, label %for.body.lr.ph.i81
+
+for.body.lr.ph.i81:                               ; preds = %if.then165
+  br label %for.body.i86
+
+for.body.i86:                                     ; preds = %for.end.i129, %for.body.lr.ph.i81
+  %cmp196.i = icmp ult i32 0, undef
+  br i1 %cmp196.i, label %for.body21.lr.ph.i, label %for.end.i129
+
+for.body21.lr.ph.i:                               ; preds = %for.body.i86
+  br label %for.body21.i
+
+for.body21.i:
+  %destYPixelPtr.010.i = phi i8* [ null, %for.body21.lr.ph.i ], [ %incdec.ptr.i, %if.end.i126 ]
+  %x.09.i = phi i32 [ 0, %for.body21.lr.ph.i ], [ %inc.i125, %if.end.i126 ]
+  br i1 undef, label %if.end.i126, label %if.else.i124
+
+if.else.i124:                                     ; preds = %for.body21.i
+  store i8 undef, i8* %destYPixelPtr.010.i, align 1
+  br label %if.end.i126
+
+if.end.i126:                                      ; preds = %if.else.i124, %for.body21.i
+  %incdec.ptr.i = getelementptr inbounds i8* %destYPixelPtr.010.i, i32 1
+  %inc.i125 = add i32 %x.09.i, 1
+  %cmp19.i = icmp ult i32 %inc.i125, undef
+  br i1 %cmp19.i, label %for.body21.i, label %for.end.i129
+
+for.end.i129:                                     ; preds = %if.end.i126, %for.body.i86
+  br i1 undef, label %for.body.i86, label %while.cond
+
+while.end:                                        ; preds = %while.cond
+  br label %bail
+
+bail:                                             ; preds = %while.end, %lor.lhs.false44, %lor.lhs.false41, %if.end29, %if.end
+  unreachable
+
+return:                                           ; preds = %lor.lhs.false20, %lor.lhs.false12, %lor.lhs.false, %entry
+  ret void
+}