[llvm] r335931 - [ARM] Assert that ARMDAGToDAGISel creates valid UBFX/SBFX nodes.

[Eli Friedman via llvm-commits]

Author: efriedma
Date: Thu Jun 28 14:49:41 2018
New Revision: 335931

URL: http://llvm.org/viewvc/llvm-project?rev=335931&view=rev
Log:
[ARM] Assert that ARMDAGToDAGISel creates valid UBFX/SBFX nodes.

We don't ever check these again (unless you're using
-fno-integrated-as), so make sure the extracted bits are well-defined.

I don't think it's possible to trigger any of the assertions on trunk,
but it's difficult to prove.  (The first one depends on DAGCombine to
minimize the number of set bits in AND masks; I think the others are
mathematically impossible to hit.)


Modified:
    llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp

Modified: llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp?rev=335931&r1=335930&r2=335931&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp Thu Jun 28 14:49:41 2018
@@ -2337,6 +2337,7 @@ bool ARMDAGToDAGISel::tryV6T2BitfieldExt
           return true;
         }
 
+        assert(LSB + Width + 1 <= 32 && "Shouldn't create an invalid ubfx");
         SDValue Ops[] = { N->getOperand(0).getOperand(0),
                           CurDAG->getTargetConstant(LSB, dl, MVT::i32),
                           CurDAG->getTargetConstant(Width, dl, MVT::i32),
@@ -2361,6 +2362,7 @@ bool ARMDAGToDAGISel::tryV6T2BitfieldExt
       if (LSB < 0)
         return false;
       SDValue Reg0 = CurDAG->getRegister(0, MVT::i32);
+      assert(LSB + Width + 1 <= 32 && "Shouldn't create an invalid ubfx");
       SDValue Ops[] = { N->getOperand(0).getOperand(0),
                         CurDAG->getTargetConstant(LSB, dl, MVT::i32),
                         CurDAG->getTargetConstant(Width, dl, MVT::i32),
@@ -2382,6 +2384,7 @@ bool ARMDAGToDAGISel::tryV6T2BitfieldExt
       // Note: The width operand is encoded as width-1.
       unsigned Width = MSB - LSB;
       SDValue Reg0 = CurDAG->getRegister(0, MVT::i32);
+      assert(Srl_imm + Width + 1 <= 32 && "Shouldn't create an invalid ubfx");
       SDValue Ops[] = { N->getOperand(0).getOperand(0),
                         CurDAG->getTargetConstant(Srl_imm, dl, MVT::i32),
                         CurDAG->getTargetConstant(Width, dl, MVT::i32),
@@ -2402,6 +2405,7 @@ bool ARMDAGToDAGISel::tryV6T2BitfieldExt
       return false;
 
     SDValue Reg0 = CurDAG->getRegister(0, MVT::i32);
+    assert(LSB + Width <= 32 && "Shouldn't create an invalid ubfx");
     SDValue Ops[] = { N->getOperand(0).getOperand(0),
                       CurDAG->getTargetConstant(LSB, dl, MVT::i32),
                       CurDAG->getTargetConstant(Width - 1, dl, MVT::i32),