[PATCH] D126205: [PowerPC] use BL without nop for some internal calls for fast-isel.

[ChenZheng via Phabricator via llvm-commits]

shchenz created this revision.
shchenz added reviewers: umesh.kalappa0, nemanjai, PowerPC.
Herald added subscribers: kbarton, hiraditya.
Herald added a project: All.
shchenz requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

This fixes pr55607. Now we can generate BL without nop instruction for internal function for fast-isel.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D126205

Files:
  llvm/lib/Target/PowerPC/PPCFastISel.cpp
  llvm/test/CodeGen/PowerPC/pr55607.ll


Index: llvm/test/CodeGen/PowerPC/pr55607.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/PowerPC/pr55607.ll
@@ -0,0 +1,39 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -ppc-asm-full-reg-names -ppc-vsr-nums-as-vr -fast-isel \
+; RUN:   -mtriple=powerpc64le-unknown-unknown < %s | FileCheck %s
+
+define dso_local signext i32 @callee() {
+; CHECK-LABEL: callee:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    li r3, 0
+; CHECK-NEXT:    blr
+entry:
+  ret i32 0
+}
+
+define dso_local signext i32 @foo() nounwind {
+; CHECK-LABEL: foo:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    mflr r0
+; CHECK-NEXT:    std r30, -16(r1) # 8-byte Folded Spill
+; CHECK-NEXT:    std r0, 16(r1)
+; CHECK-NEXT:    stdu r1, -112(r1)
+; CHECK-NEXT:    bl callee
+; CHECK-NEXT:    mr r30, r3
+; CHECK-NEXT:    bl callee2
+; CHECK-NEXT:    nop
+; CHECK-NEXT:    add r3, r30, r3
+; CHECK-NEXT:    extsw r3, r3
+; CHECK-NEXT:    addi r1, r1, 112
+; CHECK-NEXT:    ld r0, 16(r1)
+; CHECK-NEXT:    ld r30, -16(r1) # 8-byte Folded Reload
+; CHECK-NEXT:    mtlr r0
+; CHECK-NEXT:    blr
+entry:
+  %call = call signext i32 @callee()
+  %call1 = call signext i32 @callee2()
+  %add = add nsw i32 %call, %call1
+  ret i32 %add
+}
+
+declare signext i32 @callee2()
Index: llvm/lib/Target/PowerPC/PPCFastISel.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCFastISel.cpp
+++ llvm/lib/Target/PowerPC/PPCFastISel.cpp
@@ -1661,10 +1661,12 @@
     else
       return false;
   } else {
-    // Build direct call with NOP for TOC restore.
-    // FIXME: We can and should optimize away the NOP for local calls.
-    MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
-                  TII.get(PPC::BL8_NOP));
+    // Build direct call.
+    bool ShareTOCBase = !Subtarget->isUsingPCRelativeCalls() &&
+                        Subtarget->getTargetLowering()->callsShareTOCBase(
+                            &FuncInfo.MF->getFunction(), GV);
+    unsigned CallOP = ShareTOCBase ? PPC::BL8 : PPC::BL8_NOP;
+    MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(CallOP));
     // Add callee.
     MIB.addGlobalAddress(GV);
   }


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D126205.431364.patch
Type: text/x-patch
Size: 2278 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220523/034393c0/attachment.bin>