[PATCH] D101470: [XCOFF][AIX] Peephole optimization in TocData transformation

[Sidharth Baveja via Phabricator via llvm-commits]

sidbav created this revision.
sidbav added reviewers: sfertile, hubert.reinterpretcast, daltenty, jasonliu.
Herald added subscribers: kbarton, hiraditya, nemanjai.
sidbav requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

This patch is a followup to D101178 <https://reviews.llvm.org/D101178>.

In the patch, we enable peephole optimization (when possible) for the toc data transformation.

For example, with this patch would allow for the following assembly code:

  la 4, i[TD](2) 
  stw 3, 0(4)

to be transformed to the following instead:

  stw 3, i[TD](2)

This patch can only be merged in after D101178 <https://reviews.llvm.org/D101178> has been accepted and merged into LLVM.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D101470

Files:
  llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
  llvm/lib/Target/PowerPC/PPCMCInstLower.cpp
  llvm/test/CodeGen/PowerPC/toc-data.ll


Index: llvm/test/CodeGen/PowerPC/toc-data.ll
===================================================================
--- llvm/test/CodeGen/PowerPC/toc-data.ll
+++ llvm/test/CodeGen/PowerPC/toc-data.ll
@@ -14,12 +14,11 @@
     ret void
 }
 ; CHECK: name:            write_int
-; CHECK:      %[[SCRATCH:[0-9]+]]:gprc_and_gprc_nor0 = ADDItoc @i, $r2
-; CHECK-NEXT: STW %{{[0-9]+}}, 0, killed %[[SCRATCH]] :: (store 4 into @i)
+; CHECK:      %[[SCRATCH:[0-9]+]]:gprc  = COPY $r3
+; CHECK-NEXT: STW %{{[0-9]+}}, @i, $r2 :: (store 4 into @i)
 
 ; TEST:         .write_int:
-; TEST:         la 4, i[TD](2)
-; TEST-NEXT:    stw 3, 0(4)
+; TEST:    stw 3, i[TD](2)
 
 define dso_local i64 @read_ll() {
   entry:
@@ -40,12 +39,10 @@
     ret float %0
 }
 ; CHECK: name:            read_float
-; CHECK: %[[SCRATCH:[0-9]+]]:gprc_and_gprc_nor0 = ADDItoc @f, $r2
-; CHECK: %{{[0-9]+}}:f4rc = LFS 0, killed %[[SCRATCH]] :: (dereferenceable load 4 from @f)
+; CHECK: %{{[0-9]+}}:f4rc = LFS @f, $r2 :: (dereferenceable load 4 from @f)
 
 ; TEST:       .read_float:
-; TEST:       la 3, f[TD](2)
-; TEST-NEXT:  lfs 1, 0(3)
+; TEST:  lfs 1, f[TD](2)
 
 define dso_local void @write_double(double %in) {
   entry:
@@ -76,7 +73,8 @@
     ret i32 %0
 }
 ; CHECK: name:            read_i32_linkage
-; CHECK: LWZtoc @ilocal, $r2 :: (load 4 from got)
+; CHECK:      %[[SCRATCH:[0-9]+]]:gprc_and_gprc_nor0 = LWZtoc @ilocal, $r2 :: (load 4 from got)
+; CHECK-NEXT: LWZ 0, killed %[[SCRATCH]] :: (dereferenceable load 4 from @ilocal)
 
 ; TEST:       .read_i32_linkage:
 ; TEST:       lwz 3, L..C2(2)
Index: llvm/lib/Target/PowerPC/PPCMCInstLower.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCMCInstLower.cpp
+++ llvm/lib/Target/PowerPC/PPCMCInstLower.cpp
@@ -42,6 +42,11 @@
     Mangler::getNameWithPrefix(Name, MO.getSymbolName(), DL);
   } else {
     const GlobalValue *GV = MO.getGlobal();
+
+    if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
+      if (GVar->hasAttribute("toc-data"))
+        return AP.getSymbol(GV);
+
     TM.getNameWithPrefix(Name, GV, Mang);
   }
 
Index: llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -7092,6 +7092,7 @@
       Flags = PPCII::MO_TLSLD_LO;
       break;
     case PPC::ADDItocL:
+    case PPC::ADDItoc:
       Flags = PPCII::MO_TOC_LO;
       break;
     }
@@ -7189,9 +7190,18 @@
     }
 
     if (FirstOp == 1) // Store
-      (void)CurDAG->UpdateNodeOperands(N, N->getOperand(0), ImmOpnd,
-                                       Base.getOperand(0), N->getOperand(3));
+      if (Base.getMachineOpcode() == PPC::ADDItoc)
+        (void)CurDAG->UpdateNodeOperands(N, N->getOperand(0),
+                                         Base.getOperand(0), Base.getOperand(1),
+                                         N->getOperand(3));
+      else
+        (void)CurDAG->UpdateNodeOperands(N, N->getOperand(0), ImmOpnd,
+                                         Base.getOperand(0), N->getOperand(3));
     else // Load
+        if (Base.getMachineOpcode() == PPC::ADDItoc)
+      (void)CurDAG->UpdateNodeOperands(N, Base.getOperand(0),
+                                       Base.getOperand(1), N->getOperand(2));
+    else
       (void)CurDAG->UpdateNodeOperands(N, ImmOpnd, Base.getOperand(0),
                                        N->getOperand(2));
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D101470.341240.patch
Type: text/x-patch
Size: 3501 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20210428/ffd11f11/attachment.bin>