From 26c8dcc692fb2addd475446cfff24d6a4e958bca Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Wed, 4 Apr 2012 12:51:34 +0000
Subject: Always compute all the bits in ComputeMaskedBits. This allows us to
 keep passing reduced masks to SimplifyDemandedBits, but know about all the
 bits if SimplifyDemandedBits fails. This allows instcombine to simplify cases
 like the one in the included testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154011 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMISelLowering.cpp | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

(limited to 'lib/Target/ARM/ARMISelLowering.cpp')

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index d5c38d5e1b..fab3e24551 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -8288,8 +8288,7 @@ ARMTargetLowering::PerformCMOVCombine(SDNode *N, SelectionDAG &DAG) const {
 
   if (Res.getNode()) {
     APInt KnownZero, KnownOne;
-    APInt Mask = APInt::getAllOnesValue(VT.getScalarType().getSizeInBits());
-    DAG.ComputeMaskedBits(SDValue(N,0), Mask, KnownZero, KnownOne);
+    DAG.ComputeMaskedBits(SDValue(N,0), KnownZero, KnownOne);
     // Capture demanded bits information that would be otherwise lost.
     if (KnownZero == 0xfffffffe)
       Res = DAG.getNode(ISD::AssertZext, dl, MVT::i32, Res,
@@ -8805,22 +8804,20 @@ bool ARMTargetLowering::getPostIndexedAddressParts(SDNode *N, SDNode *Op,
 }
 
 void ARMTargetLowering::computeMaskedBitsForTargetNode(const SDValue Op,
-                                                       const APInt &Mask,
                                                        APInt &KnownZero,
                                                        APInt &KnownOne,
                                                        const SelectionDAG &DAG,
                                                        unsigned Depth) const {
-  KnownZero = KnownOne = APInt(Mask.getBitWidth(), 0);
+  KnownZero = KnownOne = APInt(KnownOne.getBitWidth(), 0);
   switch (Op.getOpcode()) {
   default: break;
   case ARMISD::CMOV: {
     // Bits are known zero/one if known on the LHS and RHS.
-    DAG.ComputeMaskedBits(Op.getOperand(0), Mask, KnownZero, KnownOne, Depth+1);
+    DAG.ComputeMaskedBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
     if (KnownZero == 0 && KnownOne == 0) return;
 
     APInt KnownZeroRHS, KnownOneRHS;
-    DAG.ComputeMaskedBits(Op.getOperand(1), Mask,
-                          KnownZeroRHS, KnownOneRHS, Depth+1);
+    DAG.ComputeMaskedBits(Op.getOperand(1), KnownZeroRHS, KnownOneRHS, Depth+1);
     KnownZero &= KnownZeroRHS;
     KnownOne  &= KnownOneRHS;
     return;
-- 
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