[llvm] a08cbab - [MC] Optimize relaxInstruction: remove SmallVector copy. NFC

[Fangrui Song via llvm-commits]

Author: Fangrui Song
Date: 2023-05-04T23:34:35-07:00
New Revision: a08cbabb28e5e5f27ce802e1b26ba273a071a0f3

URL: https://github.com/llvm/llvm-project/commit/a08cbabb28e5e5f27ce802e1b26ba273a071a0f3
DIFF: https://github.com/llvm/llvm-project/commit/a08cbabb28e5e5f27ce802e1b26ba273a071a0f3.diff

LOG: [MC] Optimize relaxInstruction: remove SmallVector copy. NFC

Added: 
    

Modified: 
    llvm/lib/MC/MCAssembler.cpp

Removed: 
    


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diff  --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index 159b6a8ffc984..8d87bcb5dc202 100644
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -990,18 +990,11 @@ bool MCAssembler::relaxInstruction(MCAsmLayout &Layout,
   getBackend().relaxInstruction(Relaxed, *F.getSubtargetInfo());
 
   // Encode the new instruction.
-  //
-  // FIXME-PERF: If it matters, we could let the target do this. It can
-  // probably do so more efficiently in many cases.
-  SmallVector<MCFixup, 4> Fixups;
-  SmallString<256> Code;
-  getEmitter().encodeInstruction(Relaxed, Code, Fixups, *F.getSubtargetInfo());
-
-  // Update the fragment.
   F.setInst(Relaxed);
-  F.getContents() = Code;
-  F.getFixups() = Fixups;
-
+  F.getFixups().clear();
+  F.getContents().clear();
+  getEmitter().encodeInstruction(Relaxed, F.getContents(), F.getFixups(),
+                                 *F.getSubtargetInfo());
   return true;
 }