From: Chris Lattner <sabre@nondot.org>
Date: Sun, 21 Aug 2005 18:03:09 +0000 (+0000)
Subject: When legalizing brcond ->brcc or select -> selectcc, make sure to truncate
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=550b1e59c4eb5db020766012b1406fc56833251d;p=oota-llvm.git

When legalizing brcond ->brcc or select -> selectcc, make sure to truncate
the old condition to a one bit value.  The incoming value must have been
promoted, and the top bits are undefined.  This causes us to generate:

_test:
        rlwinm r2, r3, 0, 31, 31
        li r3, 17
        cmpwi cr0, r2, 0
        bne .LBB_test_2 ;
.LBB_test_1:    ;
        li r3, 1
.LBB_test_2:    ;
        blr

instead of:

_test:
        rlwinm r2, r3, 0, 31, 31
        li r2, 17
        cmpwi cr0, r3, 0
        bne .LBB_test_2 ;
.LBB_test_1:    ;
        li r2, 1
.LBB_test_2:    ;
        or r3, r2, r2
        blr

for:

int %test(bool %c) {
        %retval = select bool %c, int 17, int 1
        ret int %retval
}


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22947 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 2c01982df2b..3b686b95c70 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -681,6 +681,10 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
                              Tmp2.getOperand(0), Tmp2.getOperand(1),
                              Node->getOperand(2));
       } else {
+        // Make sure the condition is either zero or one.  It may have been
+        // promoted from something else.
+        Tmp2 = DAG.getZeroExtendInReg(Tmp2, MVT::i1);
+        
         Result = DAG.getNode(ISD::BR_CC, MVT::Other, Tmp1, 
                              DAG.getCondCode(ISD::SETNE), Tmp2,
                              DAG.getConstant(0, Tmp2.getValueType()),
@@ -1072,6 +1076,9 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
                               Tmp2, Tmp3,
                               cast<CondCodeSDNode>(Tmp1.getOperand(2))->get());
       } else {
+        // Make sure the condition is either zero or one.  It may have been
+        // promoted from something else.
+        Tmp1 = DAG.getZeroExtendInReg(Tmp1, MVT::i1);
         Result = DAG.getSelectCC(Tmp1, 
                                  DAG.getConstant(0, Tmp1.getValueType()),
                                  Tmp2, Tmp3, ISD::SETNE);