[PATCH] D47214: [InstCombine] Replace bcmp/bcopy with memcmp/memmove

Dávid Bolvanský via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue May 22 12:04:47 PDT 2018


xbolva00 created this revision.
xbolva00 added a reviewer: bkramer.
Herald added a subscriber: llvm-commits.

bcmp(s1, s2, n) -> memcmp(s1, s2, n)
bcopy(src, dst, n) -> memmove(dst, src, n)


Repository:
  rL LLVM

https://reviews.llvm.org/D47214

Files:
  include/llvm/Transforms/Utils/SimplifyLibCalls.h
  lib/Transforms/Utils/SimplifyLibCalls.cpp
  test/Transforms/InstCombine/bcmp-bcopy.ll


Index: test/Transforms/InstCombine/bcmp-bcopy.ll
===================================================================
--- test/Transforms/InstCombine/bcmp-bcopy.ll
+++ test/Transforms/InstCombine/bcmp-bcopy.ll
@@ -0,0 +1,26 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128"
+
+declare i32 @bcmp(i8* nocapture, i8* nocapture, i32)
+declare void @bcopy(i8* nocapture readonly, i8* nocapture, i32)
+
+define i32 @bcmp_memcmp(i8* nocapture readonly %a, i8* nocapture readonly %b, i32 %len) {
+; CHECK-LABEL: @bcmp_memcmp(
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* [[A:%.*]], i8* [[B:%.*]], i32 [[LEN:%.*]])
+; CHECK-NEXT:    ret i32 [[MEMCMP]]
+;
+  %call = tail call i32 @bcmp(i8* %a, i8* %b, i32 %len) #4
+  ret i32 %call
+}
+
+define void @bcopy_memmove(i8* nocapture readonly %a, i8* nocapture %b, i32 %len) {
+; CHECK-LABEL: @bcopy_memmove(
+; CHECK-NEXT:    call void @llvm.memmove.p0i8.p0i8.i32(i8* align 1 [[B:%.*]], i8* align 1 [[A:%.*]], i32 [[LEN:%.*]], i1 false)
+; CHECK-NEXT:    ret void
+;
+  tail call void @bcopy(i8* %a, i8* %b, i32 %len) #5
+  ret void
+}
+
Index: lib/Transforms/Utils/SimplifyLibCalls.cpp
===================================================================
--- lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -2204,6 +2204,18 @@
   return nullptr;
 }
 
+Value *LibCallSimplifier::optimizeBCmp(CallInst *CI, IRBuilder<> &B) {
+  // bcmp(s1, s2, n) -> memcmp(s1, s2, n)
+  return emitMemCmp(CI->getOperand(0), CI->getOperand(1), CI->getOperand(2), B,
+                    DL, TLI);
+}
+
+Value *LibCallSimplifier::optimizeBCopy(CallInst *CI, IRBuilder<> &B) {
+  // bcopy(src, dst, n) -> memmove(dst, src, n)
+  return B.CreateMemMove(CI->getArgOperand(1), 1, CI->getArgOperand(0), 1,
+                         CI->getArgOperand(2));
+}
+
 bool LibCallSimplifier::hasFloatVersion(StringRef FuncName) {
   LibFunc Func;
   SmallString<20> FloatFuncName = FuncName;
@@ -2274,6 +2286,10 @@
       return optimizeRealloc(CI, Builder);
     case LibFunc_wcslen:
       return optimizeWcslen(CI, Builder);
+    case LibFunc_bcmp:
+      return optimizeBCmp(CI, Builder);
+    case LibFunc_bcopy:
+      return optimizeBCopy(CI, Builder);
     default:
       break;
     }
Index: include/llvm/Transforms/Utils/SimplifyLibCalls.h
===================================================================
--- include/llvm/Transforms/Utils/SimplifyLibCalls.h
+++ include/llvm/Transforms/Utils/SimplifyLibCalls.h
@@ -126,6 +126,8 @@
   Value *optimizeMemSet(CallInst *CI, IRBuilder<> &B);
   Value *optimizeRealloc(CallInst *CI, IRBuilder<> &B);
   Value *optimizeWcslen(CallInst *CI, IRBuilder<> &B);
+  Value *optimizeBCmp(CallInst *CI, IRBuilder<> &B);
+  Value *optimizeBCopy(CallInst *CI, IRBuilder<> &B);
   // Wrapper for all String/Memory Library Call Optimizations
   Value *optimizeStringMemoryLibCall(CallInst *CI, IRBuilder<> &B);
 


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