[llvm-commits] CVS: llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp

[Chris Lattner]

Changes in directory llvm/lib/CodeGen/SelectionDAG:

LegalizeDAG.cpp updated: 1.60 -> 1.61
---
Log message:

Fix a bug in the 'store fpimm, ptr' -> 'store intimm, ptr' handling code. 
Changing 'op' here caused us to not enter the store into a map, causing 
reemission of the code!!  In practice, a simple loop like this:

no_exit:                ; preds = %no_exit, %entry
        %indvar = phi uint [ %indvar.next, %no_exit ], [ 0, %entry ]            ; <uint> [#uses=3]
        %tmp.4 = getelementptr "complex long double"* %P, uint %indvar, uint 0          ; <double*> [#uses=1]
        store double 0.000000e+00, double* %tmp.4
        %indvar.next = add uint %indvar, 1              ; <uint> [#uses=2]
        %exitcond = seteq uint %indvar.next, %N         ; <bool> [#uses=1]
        br bool %exitcond, label %return, label %no_exit

was being code gen'd to:

.LBBtest_1:     # no_exit
        movl %edx, %esi
        shll $4, %esi
        movl $0, 4(%eax,%esi)
        movl $0, (%eax,%esi)
        incl %edx
        movl $0, (%eax,%esi)
        movl $0, 4(%eax,%esi)
        cmpl %ecx, %edx
        jne .LBBtest_1  # no_exit

Note that we are doing 4 32-bit stores instead of 2.  Now we generate:

.LBBtest_1:     # no_exit
        movl %edx, %esi
        incl %esi
        shll $4, %edx
        movl $0, (%eax,%edx)
        movl $0, 4(%eax,%edx)
        cmpl %ecx, %esi
        movl %esi, %edx
        jne .LBBtest_1  # no_exit

This is much happier, though it would be even better if the increment of ESI
was scheduled after the compare :-/



---
Diffs of the changes:  (+1 -2)

 LegalizeDAG.cpp |    3 +--
 1 files changed, 1 insertion(+), 2 deletions(-)


Index: llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:1.60 llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:1.61
--- llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:1.60	Fri Feb  4 12:39:19 2005
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp	Tue Feb 22 01:23:39 2005
@@ -515,8 +515,7 @@
         Result = DAG.getNode(ISD::STORE, MVT::Other, Tmp1,
                              DAG.getConstant(V.I, MVT::i64), Tmp2);
       }
-      Op = Result;
-      Node = Op.Val;
+      Node = Result.Val;
     }
 
     switch (getTypeAction(Node->getOperand(1).getValueType())) {