From 41502e1af77443c31138cee309bd89898f23e33a Mon Sep 17 00:00:00 2001
From: Michael Gottesman <mgottesman@apple.com>
Date: Tue, 18 Jun 2013 20:49:45 +0000
Subject: [ARMTargetLowering] ARMISD::{SUB,ADD}{C,E} second result is a boolean
 implying that upper bits are always 0.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184231 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMISelLowering.cpp | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

(limited to 'lib/Target')

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 015b023dca..a63cb27b1e 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -10184,9 +10184,19 @@ void ARMTargetLowering::computeMaskedBitsForTargetNode(const SDValue Op,
                                                        APInt &KnownOne,
                                                        const SelectionDAG &DAG,
                                                        unsigned Depth) const {
-  KnownZero = KnownOne = APInt(KnownOne.getBitWidth(), 0);
+  unsigned BitWidth = KnownOne.getBitWidth();
+  KnownZero = KnownOne = APInt(BitWidth, 0);
   switch (Op.getOpcode()) {
   default: break;
+  case ARMISD::ADDC:
+  case ARMISD::ADDE:
+  case ARMISD::SUBC:
+  case ARMISD::SUBE:
+    // These nodes' second result is a boolean
+    if (Op.getResNo() == 0)
+      break;
+    KnownZero |= APInt::getHighBitsSet(BitWidth, BitWidth - 1);
+    break;
   case ARMISD::CMOV: {
     // Bits are known zero/one if known on the LHS and RHS.
     DAG.ComputeMaskedBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
-- 
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