[ExpandMemCmp] Trigger on bcmp too.

[courbet]

Summary

Fixes 41150.

llvm/trunk/lib/CodeGen/ExpandMemCmp.cpp

bool ExpandMemCmpPass::runOnBlock(
     const DataLayout& DL) {
   for (Instruction& I : BB) {
     CallInst *CI = dyn_cast<CallInst>(&I);
     if (!CI) {
       continue;
     }
     LibFunc Func;
     if (TLI->getLibFunc(ImmutableCallSite(CI), Func) &&
-        Func == LibFunc_memcmp && expandMemCmp(CI, TTI, TL, &DL)) {
+        (Func == LibFunc_memcmp || Func == LibFunc_bcmp) &&
+        expandMemCmp(CI, TTI, TL, &DL)) {
       return true;
     }
   }
   return false;
 }
 
 
 PreservedAnalyses ExpandMemCmpPass::runImpl(

llvm/trunk/test/CodeGen/X86/memcmp-optsize.ll

 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc < %s -mtriple=i686-unknown-unknown -mattr=cmov | FileCheck %s --check-prefix=X86 --check-prefix=X86-NOSSE
 ; RUN: llc < %s -mtriple=i686-unknown-unknown -mattr=+sse2 | FileCheck %s --check-prefix=X86 --check-prefix=X86-SSE2
 ; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s --check-prefix=X64 --check-prefix=X64-SSE2
 ; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx2 | FileCheck %s --check-prefix=X64 --check-prefix=X64-AVX2
 
 ; This tests codegen time inlining/optimization of memcmp
 ; rdar://6480398
 
 @.str = private constant [65 x i8] c"0123456789012345678901234567890123456789012345678901234567890123\00", align 1
 
 declare i32 @memcmp(i8*, i8*, i64)
+declare i32 @bcmp(i8*, i8*, i64)
 
 define i32 @length2(i8* %X, i8* %Y) nounwind optsize {
 ; X86-LABEL: length2:
 ; X86:       # %bb.0:
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
 ; X86-NEXT:    movzwl (%ecx), %ecx
 ; X86-NEXT:    movzwl (%eax), %edx

 ; X64-AVX2-NEXT:    sete %al
 ; X64-AVX2-NEXT:    vzeroupper
 ; X64-AVX2-NEXT:    retq
   %m = tail call i32 @memcmp(i8* %X, i8* getelementptr inbounds ([65 x i8], [65 x i8]* @.str, i32 0, i32 0), i64 64) nounwind
   %c = icmp eq i32 %m, 0
   ret i1 %c
 }
 
+define i32 @bcmp_length2(i8* %X, i8* %Y) nounwind optsize {
+; X86-LABEL: bcmp_length2:
+; X86:       # %bb.0:
+; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
+; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; X86-NEXT:    movzwl (%ecx), %ecx
+; X86-NEXT:    movzwl (%eax), %edx
+; X86-NEXT:    rolw $8, %cx
+; X86-NEXT:    rolw $8, %dx
+; X86-NEXT:    movzwl %cx, %eax
+; X86-NEXT:    movzwl %dx, %ecx
+; X86-NEXT:    subl %ecx, %eax
+; X86-NEXT:    retl
+;
+; X64-LABEL: bcmp_length2:
+; X64:       # %bb.0:
+; X64-NEXT:    movzwl (%rdi), %eax
+; X64-NEXT:    movzwl (%rsi), %ecx
+; X64-NEXT:    rolw $8, %ax
+; X64-NEXT:    rolw $8, %cx
+; X64-NEXT:    movzwl %ax, %eax
+; X64-NEXT:    movzwl %cx, %ecx
+; X64-NEXT:    subl %ecx, %eax
+; X64-NEXT:    retq
+  %m = tail call i32 @bcmp(i8* %X, i8* %Y, i64 2) nounwind
+  ret i32 %m
+}
+