Much improved pic jumptable codegen:

Then:
        call    "L1$pb"
"L1$pb":
        popl    %eax
		...
LBB1_1: # entry
        imull   $4, %ecx, %ecx
        leal    LJTI1_0-"L1$pb"(%eax), %edx
        addl    LJTI1_0-"L1$pb"(%ecx,%eax), %edx
        jmpl    *%edx

        .align  2
        .set L1_0_set_3,LBB1_3-LJTI1_0
        .set L1_0_set_2,LBB1_2-LJTI1_0
        .set L1_0_set_5,LBB1_5-LJTI1_0
        .set L1_0_set_4,LBB1_4-LJTI1_0
LJTI1_0:
        .long    L1_0_set_3
        .long    L1_0_set_2

Now:
        call    "L1$pb"
"L1$pb":
        popl    %eax
		...
LBB1_1: # entry
        addl    LJTI1_0-"L1$pb"(%eax,%ecx,4), %eax
        jmpl    *%eax

		.align  2
		.set L1_0_set_3,LBB1_3-"L1$pb"
		.set L1_0_set_2,LBB1_2-"L1$pb"
		.set L1_0_set_5,LBB1_5-"L1$pb"
		.set L1_0_set_4,LBB1_4-"L1$pb"
LJTI1_0:
        .long    L1_0_set_3
        .long    L1_0_set_2


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43924 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 11 deletions

diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 6e58631f0c..0731299f35 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1599,21 +1599,17 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
       case 8: LD = DAG.getLoad(MVT::i64, Chain, Addr, NULL, 0); break;
       }
 
+      Addr = LD;
       if (TLI.getTargetMachine().getRelocationModel() == Reloc::PIC_) {
         // For PIC, the sequence is:
         // BRIND(load(Jumptable + index) + RelocBase)
-        // RelocBase is the JumpTable on PPC and X86, GOT on Alpha
-        SDOperand Reloc;
-        if (TLI.usesGlobalOffsetTable())
-          Reloc = DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, PTy);
-        else
-          Reloc = Table;
-        Addr = (PTy != MVT::i32) ? DAG.getNode(ISD::SIGN_EXTEND, PTy, LD) : LD;
-        Addr = DAG.getNode(ISD::ADD, PTy, Addr, Reloc);
-        Result = DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), Addr);
-      } else {
-        Result = DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), LD);
+        // RelocBase can be JumpTable, GOT or some sort of global base.
+        if (PTy != MVT::i32)
+          Addr = DAG.getNode(ISD::SIGN_EXTEND, PTy, Addr);
+        Addr = DAG.getNode(ISD::ADD, PTy, Addr,
+                           TLI.getPICJumpTableRelocBase(Table, DAG));
       }
+      Result = DAG.getNode(ISD::BRIND, MVT::Other, LD.getValue(1), Addr);
     }
     }
     break;