[llvm-commits] [llvm] r51240 - in /llvm/trunk: lib/Transforms/Scalar/SimplifyLibCalls.cpp test/Transforms/SimplifyLibCalls/2008-05-19-memcmp.ll

[Duncan Sands]

Author: baldrick
Date: Mon May 19 04:27:24 2008
New Revision: 51240

URL: http://llvm.org/viewvc/llvm-project?rev=51240&view=rev
Log:
Fix PR2341 - when the length is 4 use an i32 not
an i16!  Cleaned up trailing whitespace while there.

Added:
    llvm/trunk/test/Transforms/SimplifyLibCalls/2008-05-19-memcmp.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/SimplifyLibCalls.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/SimplifyLibCalls.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SimplifyLibCalls.cpp?rev=51240&r1=51239&r2=51240&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SimplifyLibCalls.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SimplifyLibCalls.cpp Mon May 19 04:27:24 2008
@@ -731,17 +731,17 @@
         !isa<PointerType>(FT->getParamType(1)) ||
         FT->getReturnType() != Type::Int32Ty)
       return 0;
-    
+
     Value *LHS = CI->getOperand(1), *RHS = CI->getOperand(2);
-    
+
     if (LHS == RHS)  // memcmp(s,s,x) -> 0
       return Constant::getNullValue(CI->getType());
-    
+
     // Make sure we have a constant length.
     ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getOperand(3));
     if (!LenC) return 0;
     uint64_t Len = LenC->getZExtValue();
-    
+
     if (Len == 0) // memcmp(s1,s2,0) -> 0
       return Constant::getNullValue(CI->getType());
 
@@ -750,18 +750,20 @@
       Value *RHSV = B.CreateLoad(CastToCStr(RHS, B), "rhsv");
       return B.CreateZExt(B.CreateSub(LHSV, RHSV, "chardiff"), CI->getType());
     }
-    
+
     // memcmp(S1,S2,2) != 0 -> (*(short*)LHS ^ *(short*)RHS)  != 0
     // memcmp(S1,S2,4) != 0 -> (*(int*)LHS ^ *(int*)RHS)  != 0
     if ((Len == 2 || Len == 4) && IsOnlyUsedInZeroEqualityComparison(CI)) {
-      LHS = B.CreateBitCast(LHS, PointerType::getUnqual(Type::Int16Ty), "tmp");
-      RHS = B.CreateBitCast(RHS, LHS->getType(), "tmp");
+      const Type *PTy = PointerType::getUnqual(Len == 2 ?
+                                               Type::Int16Ty : Type::Int32Ty);
+      LHS = B.CreateBitCast(LHS, PTy, "tmp");
+      RHS = B.CreateBitCast(RHS, PTy, "tmp");
       LoadInst *LHSV = B.CreateLoad(LHS, "lhsv");
       LoadInst *RHSV = B.CreateLoad(RHS, "rhsv");
       LHSV->setAlignment(1); RHSV->setAlignment(1);  // Unaligned loads.
       return B.CreateZExt(B.CreateXor(LHSV, RHSV, "shortdiff"), CI->getType());
     }
-    
+
     return 0;
   }
 };

Added: llvm/trunk/test/Transforms/SimplifyLibCalls/2008-05-19-memcmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyLibCalls/2008-05-19-memcmp.ll?rev=51240&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/SimplifyLibCalls/2008-05-19-memcmp.ll (added)
+++ llvm/trunk/test/Transforms/SimplifyLibCalls/2008-05-19-memcmp.ll Mon May 19 04:27:24 2008
@@ -0,0 +1,14 @@
+; RUN: llvm-as < %s | opt -simplify-libcalls | llvm-dis | grep i32
+; PR2341
+
+ at _2E_str = external constant [5 x i8]		; <[5 x i8]*> [#uses=1]
+
+declare i32 @memcmp(i8*, i8*, i32) nounwind readonly 
+
+define i1 @f(i8** %start_addr) {
+entry:
+	%tmp4 = load i8** %start_addr, align 4		; <i8*> [#uses=1]
+	%tmp5 = call i32 @memcmp( i8* %tmp4, i8* getelementptr ([5 x i8]* @_2E_str, i32 0, i32 0), i32 4 ) nounwind readonly 		; <i32> [#uses=1]
+	%tmp6 = icmp eq i32 %tmp5, 0		; <i1> [#uses=1]
+	ret i1 %tmp6
+}