[InstCombine] Transform str(n)cmp to memcmp

Summary:
Motivation examples:
int strcmp_memcmp() {
    char buf[12];
    return strcmp(buf, "key") == 0;
}

int strcmp_memcmp2() {
    char buf[12];
    return strcmp(buf, "key") != 0;
}

int strncmp_memcmp() {
    char buf[12];
    return strncmp(buf, "key", 3) == 0;
}

can be turned to memcmp.

See test file for more cases.

Reviewers: efriedma

Reviewed By: efriedma

Subscribers: spatel, llvm-commits

Differential Revision: https://reviews.llvm.org/D50233

llvm-svn: 339410

2 files changed, 107 insertions, 48 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 33371e71b91..67127af4a52 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -22,6 +22,7 @@
 #include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/Analysis/CaptureTracking.h"
+#include "llvm/Analysis/Loads.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
@@ -150,6 +151,29 @@ static bool isLocallyOpenedFile(Value *File, CallInst *CI, IRBuilder<> &B,
   return true;
 }
 
+static bool isOnlyUsedInComparisonWithZero(Value *V) {
+  for (User *U : V->users()) {
+    if (ICmpInst *IC = dyn_cast<ICmpInst>(U))
+      if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
+        if (C->isNullValue())
+          continue;
+    // Unknown instruction.
+    return false;
+  }
+  return true;
+}
+
+static bool canTransformToMemCmp(CallInst *CI, Value *Str, uint64_t Len,
+                                 const DataLayout &DL) {
+  if (!isOnlyUsedInComparisonWithZero(CI))
+    return false;
+
+  if (!isDereferenceableAndAlignedPointer(Str, 1, APInt(64, Len), DL))
+    return false;
+    
+  return true;
+}
+
 //===----------------------------------------------------------------------===//
 // String and Memory Library Call Optimizations
 //===----------------------------------------------------------------------===//
@@ -322,6 +346,21 @@ Value *LibCallSimplifier::optimizeStrCmp(CallInst *CI, IRBuilder<> &B) {
                       B, DL, TLI);
   }
 
+  // strcmp to memcmp
+  if (!HasStr1 && HasStr2) {
+    if (canTransformToMemCmp(CI, Str1P, Len2, DL))
+      return emitMemCmp(
+          Str1P, Str2P,
+          ConstantInt::get(DL.getIntPtrType(CI->getContext()), Len2), B, DL,
+          TLI);
+  } else if (HasStr1 && !HasStr2) {
+    if (canTransformToMemCmp(CI, Str2P, Len1, DL))
+      return emitMemCmp(
+          Str1P, Str2P,
+          ConstantInt::get(DL.getIntPtrType(CI->getContext()), Len1), B, DL,
+          TLI);
+  }
+
   return nullptr;
 }
 
@@ -361,6 +400,26 @@ Value *LibCallSimplifier::optimizeStrNCmp(CallInst *CI, IRBuilder<> &B) {
   if (HasStr2 && Str2.empty()) // strncmp(x, "", n) -> *x
     return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
 
+  uint64_t Len1 = GetStringLength(Str1P);
+  uint64_t Len2 = GetStringLength(Str2P);
+
+  // strncmp to memcmp
+  if (!HasStr1 && HasStr2) {
+    Len2 = std::min(Len2, Length);
+    if (canTransformToMemCmp(CI, Str1P, Len2, DL))
+      return emitMemCmp(
+          Str1P, Str2P,
+          ConstantInt::get(DL.getIntPtrType(CI->getContext()), Len2), B, DL,
+          TLI);
+  } else if (HasStr1 && !HasStr2) {
+    Len1 = std::min(Len1, Length);
+    if (canTransformToMemCmp(CI, Str2P, Len1, DL))
+      return emitMemCmp(
+          Str1P, Str2P,
+          ConstantInt::get(DL.getIntPtrType(CI->getContext()), Len1), B, DL,
+          TLI);
+  }
+
   return nullptr;
 }
 
diff --git a/llvm/test/Transforms/InstCombine/strcmp-memcmp.ll b/llvm/test/Transforms/InstCombine/strcmp-memcmp.ll
index 6bc9c80098c..e008b2d0caf 100644
--- a/llvm/test/Transforms/InstCombine/strcmp-memcmp.ll
+++ b/llvm/test/Transforms/InstCombine/strcmp-memcmp.ll
@@ -11,8 +11,8 @@ declare void @use(i32)
 define i32 @strcmp_memcmp([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strcmp_memcmp(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0))
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -28,8 +28,8 @@ declare i32 @strcmp(i8* nocapture, i8* nocapture)
 define i32 @strcmp_memcmp2([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strcmp_memcmp2(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]])
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -43,8 +43,8 @@ define i32 @strcmp_memcmp2([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strcmp_memcmp3([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strcmp_memcmp3(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0))
-; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -58,8 +58,8 @@ define i32 @strcmp_memcmp3([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strcmp_memcmp4([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strcmp_memcmp4(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]])
-; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -73,8 +73,8 @@ define i32 @strcmp_memcmp4([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strcmp_memcmp5([5 x i8]* dereferenceable (5) %buf) {
 ; CHECK-LABEL: @strcmp_memcmp5(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [5 x i8], [5 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strcmp(i8* nonnull align 1 [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0))
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -88,8 +88,8 @@ define i32 @strcmp_memcmp5([5 x i8]* dereferenceable (5) %buf) {
 define i32 @strcmp_memcmp6([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strcmp_memcmp6(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0))
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -103,9 +103,9 @@ define i32 @strcmp_memcmp6([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strcmp_memcmp7([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strcmp_memcmp7(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]])
-; CHECK-NEXT:    [[CALL_LOBIT:%.*]] = lshr i32 [[CALL]], 31
-; CHECK-NEXT:    ret i32 [[CALL_LOBIT]]
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 4)
+; CHECK-NEXT:    [[MEMCMP_LOBIT:%.*]] = lshr i32 [[MEMCMP]], 31
+; CHECK-NEXT:    ret i32 [[MEMCMP_LOBIT]]
 ;
   %string = getelementptr inbounds [12 x i8], [12 x i8]* %buf, i64 0, i64 0
   %call = call i32 @strcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull %string)
@@ -117,8 +117,8 @@ define i32 @strcmp_memcmp7([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strcmp_memcmp8([4 x i8]* dereferenceable (4) %buf) {
 ; CHECK-LABEL: @strcmp_memcmp8(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [4 x i8], [4 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0))
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -132,8 +132,8 @@ define i32 @strcmp_memcmp8([4 x i8]* dereferenceable (4) %buf) {
 define i32 @strcmp_memcmp9([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strcmp_memcmp9(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([8 x i8], [8 x i8]* @abc, i64 0, i64 0))
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([8 x i8], [8 x i8]* @abc, i64 0, i64 0), i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -148,8 +148,8 @@ define i32 @strcmp_memcmp9([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 2)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 2)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -165,8 +165,8 @@ declare i32 @strncmp(i8* nocapture, i8* nocapture, i64)
 define i32 @strncmp_memcmp2([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp2(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 11)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -180,8 +180,8 @@ define i32 @strncmp_memcmp2([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp3([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp3(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 11)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -195,8 +195,8 @@ define i32 @strncmp_memcmp3([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp4([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp4(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 5)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -210,8 +210,8 @@ define i32 @strncmp_memcmp4([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp5([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp5(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 5)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -226,8 +226,8 @@ define i32 @strncmp_memcmp5([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp6([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp6(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 5)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ne i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -241,8 +241,8 @@ define i32 @strncmp_memcmp6([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp7([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp7(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 4)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -256,8 +256,8 @@ define i32 @strncmp_memcmp7([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp8([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp8(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 3)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i64 3)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -271,8 +271,8 @@ define i32 @strncmp_memcmp8([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp9([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp9(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 5)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -286,9 +286,9 @@ define i32 @strncmp_memcmp9([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp10([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp10(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 5)
-; CHECK-NEXT:    [[CALL_LOBIT:%.*]] = lshr i32 [[CALL]], 31
-; CHECK-NEXT:    ret i32 [[CALL_LOBIT]]
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 4)
+; CHECK-NEXT:    [[MEMCMP_LOBIT:%.*]] = lshr i32 [[MEMCMP]], 31
+; CHECK-NEXT:    ret i32 [[MEMCMP_LOBIT]]
 ;
   %string = getelementptr inbounds [12 x i8], [12 x i8]* %buf, i64 0, i64 0
   %call = call i32 @strncmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull %string, i64 5)
@@ -300,8 +300,8 @@ define i32 @strncmp_memcmp10([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp11([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp11(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 12)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -315,8 +315,8 @@ define i32 @strncmp_memcmp11([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp12([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp12(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 12)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @key, i64 0, i64 0), i8* nonnull [[STRING]], i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -330,8 +330,8 @@ define i32 @strncmp_memcmp12([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp13([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp13(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([8 x i8], [8 x i8]* @abc, i64 0, i64 0), i64 2)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([8 x i8], [8 x i8]* @abc, i64 0, i64 0), i64 2)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;
@@ -345,8 +345,8 @@ define i32 @strncmp_memcmp13([12 x i8]* dereferenceable (12) %buf) {
 define i32 @strncmp_memcmp14([12 x i8]* dereferenceable (12) %buf) {
 ; CHECK-LABEL: @strncmp_memcmp14(
 ; CHECK-NEXT:    [[STRING:%.*]] = getelementptr inbounds [12 x i8], [12 x i8]* [[BUF:%.*]], i64 0, i64 0
-; CHECK-NEXT:    [[CALL:%.*]] = call i32 @strncmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([8 x i8], [8 x i8]* @abc, i64 0, i64 0), i64 12)
-; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[CALL]], 0
+; CHECK-NEXT:    [[MEMCMP:%.*]] = call i32 @memcmp(i8* nonnull [[STRING]], i8* getelementptr inbounds ([8 x i8], [8 x i8]* @abc, i64 0, i64 0), i64 4)
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i32 [[MEMCMP]], 0
 ; CHECK-NEXT:    [[CONV:%.*]] = zext i1 [[CMP]] to i32
 ; CHECK-NEXT:    ret i32 [[CONV]]
 ;