DAGCombine: clamp hi bit in APInt::getBitsSet to avoid assertion

rdar://12838504


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169951 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 20 insertions, 2 deletions

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 1c28d6dcaf..893cf2036a 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -7433,7 +7433,8 @@ SDValue DAGCombiner::ReduceLoadOpStoreWidth(SDNode *N) {
     // start at the previous one.
     if (ShAmt % NewBW)
       ShAmt = (((ShAmt + NewBW - 1) / NewBW) * NewBW) - NewBW;
-    APInt Mask = APInt::getBitsSet(BitWidth, ShAmt, ShAmt + NewBW);
+    APInt Mask = APInt::getBitsSet(BitWidth, ShAmt,
+                                   std::min(BitWidth, ShAmt + NewBW));
     if ((Imm & Mask) == Imm) {
       APInt NewImm = (Imm & Mask).lshr(ShAmt).trunc(NewBW);
       if (Opc == ISD::AND)
diff --git a/test/CodeGen/X86/store_op_load_fold.ll b/test/CodeGen/X86/store_op_load_fold.ll
index 6e47eb397d..b1345ab23f 100644
--- a/test/CodeGen/X86/store_op_load_fold.ll
+++ b/test/CodeGen/X86/store_op_load_fold.ll
@@ -1,13 +1,30 @@
-; RUN: llc < %s -march=x86 | not grep mov
+; RUN: llc < %s -march=x86 | FileCheck %s
 ;
 ; Test the add and load are folded into the store instruction.
 
 @X = internal global i16 0              ; <i16*> [#uses=2]
 
 define void @foo() nounwind {
+; CHECK: foo:
+; CHECK-NOT: mov
+; CHECK: add
+; CHECK_NEXT: ret
         %tmp.0 = load i16* @X           ; <i16> [#uses=1]
         %tmp.3 = add i16 %tmp.0, 329            ; <i16> [#uses=1]
         store i16 %tmp.3, i16* @X
         ret void
 }
 
+; rdar://12838504
+%struct.S2 = type { i64, i16, [2 x i8], i8, [3 x i8], [7 x i8], i8, [8 x i8] }
+@s2 = external global %struct.S2, align 16
+define void @test2() nounwind uwtable ssp {
+; CHECK: test2:
+; CHECK: mov
+; CHECK-NEXT: and
+; CHECK-NEXT: ret
+  %bf.load35 = load i56* bitcast ([7 x i8]* getelementptr inbounds (%struct.S2* @s2, i32 0, i32 5) to i56*), align 16
+  %bf.clear36 = and i56 %bf.load35, -1125895611875329
+  store i56 %bf.clear36, i56* bitcast ([7 x i8]* getelementptr inbounds (%struct.S2* @s2, i32 0, i32 5) to i56*), align 16
+  ret void
+}