Disable the load-shrinking optimization from looking at

anything larger than 64-bits, avoiding a crash.  This should
really be fixed to use APInts, though type legalization happens
to help us out and we get good code on the attached testcase at
least.

This fixes rdar://6836460

llvm-svn: 70360

2 files changed, 22 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 96f815f599b..4de6e35b2e9 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1538,19 +1538,22 @@ TargetLowering::SimplifySetCC(MVT VT, SDValue N0, SDValue N1,
           N0.getOperand(0).getNode()->hasOneUse() &&
           isa<ConstantSDNode>(N0.getOperand(1))) {
         LoadSDNode *Lod = cast<LoadSDNode>(N0.getOperand(0));
-        uint64_t Mask = cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
         uint64_t bestMask = 0;
         unsigned bestWidth = 0, bestOffset = 0;
-        if (!Lod->isVolatile() && Lod->isUnindexed()) {
+        if (!Lod->isVolatile() && Lod->isUnindexed() &&
+            // FIXME: This uses getZExtValue() below so it only works on i64 and
+            // below.
+            N0.getValueType().getSizeInBits() <= 64) {
           unsigned origWidth = N0.getValueType().getSizeInBits();
           // We can narrow (e.g.) 16-bit extending loads on 32-bit target to 
           // 8 bits, but have to be careful...
           if (Lod->getExtensionType() != ISD::NON_EXTLOAD)
             origWidth = Lod->getMemoryVT().getSizeInBits();
+          uint64_t Mask =cast<ConstantSDNode>(N0.getOperand(1))->getZExtValue();
           for (unsigned width = origWidth / 2; width>=8; width /= 2) {
             uint64_t newMask = (1ULL << width) - 1;
             for (unsigned offset=0; offset<origWidth/width; offset++) {
-              if ((newMask & Mask)==Mask) {
+              if ((newMask & Mask) == Mask) {
                 if (!TD->isLittleEndian())
                   bestOffset = (origWidth/width - offset - 1) * (width/8);
                 else
diff --git a/llvm/test/CodeGen/Generic/2009-04-28-i128-cmp-crash.ll b/llvm/test/CodeGen/Generic/2009-04-28-i128-cmp-crash.ll
new file mode 100644
index 00000000000..405a6a8d6e9
--- /dev/null
+++ b/llvm/test/CodeGen/Generic/2009-04-28-i128-cmp-crash.ll
@@ -0,0 +1,16 @@
+; RUN: llvm-as < %s | llc
+; rdar://6836460
+
+define i32 @test(i128* %P) nounwind {
+entry:
+	%tmp48 = load i128* %P
+	%and49 = and i128 %tmp48, 18446744073709551616		; <i128> [#uses=1]
+	%tobool = icmp ne i128 %and49, 0		; <i1> [#uses=1]
+	br i1 %tobool, label %if.then50, label %if.end61
+
+if.then50:		; preds = %if.then20
+	ret i32 1241
+
+if.end61:		; preds = %if.then50, %if.then20, %entry
+	ret i32 123
+}