diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -2492,6 +2492,16 @@
     if (!CI->getArgOperand(2)->getType()->isPointerTy())
       return nullptr;
 
+    if (CI->use_empty())
+      // sprintf(dest, "%s", str) -> strcpy(dest, str)
+      return emitStrCpy(CI->getArgOperand(0), CI->getArgOperand(2), B, TLI);
+
+    bool OptForSize = CI->getFunction()->hasOptSize() ||
+                      llvm::shouldOptimizeForSize(CI->getParent(), PSI, BFI,
+                                                  PGSOQueryType::IRPass);
+    if (OptForSize)
+      return nullptr;
+
     Value *Len = emitStrLen(CI->getArgOperand(2), B, DL, TLI);
     if (!Len)
       return nullptr;
diff --git a/llvm/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll b/llvm/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll
--- a/llvm/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll
+++ b/llvm/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll
@@ -1,3 +1,4 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -instcombine -S < %s | FileCheck %s
 ; PR7265
 
@@ -9,10 +10,14 @@
 @.str = private constant [3 x i8] c"%s\00"
 
 define void @CopyEventArg(%union.anon* %ev) nounwind {
+; CHECK-LABEL: @CopyEventArg(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CSTR:%.*]] = bitcast %union.anon* [[EV:%.*]] to i8*
+; CHECK-NEXT:    [[STRCPY:%.*]] = call i8* @strcpy(i8* nonnull dereferenceable(1) undef, i8* nonnull dereferenceable(1) [[CSTR]])
+; CHECK-NEXT:    ret void
+;
 entry:
   %call = call i32 (i8*, i8*, ...) @sprintf(i8* undef, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), %union.anon* %ev) nounwind
-; CHECK: bitcast %union.anon* %ev to i8*
-; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64
   ret void
 }
 
diff --git a/llvm/test/Transforms/InstCombine/sprintf-1.ll b/llvm/test/Transforms/InstCombine/sprintf-1.ll
--- a/llvm/test/Transforms/InstCombine/sprintf-1.ll
+++ b/llvm/test/Transforms/InstCombine/sprintf-1.ll
@@ -81,19 +81,15 @@
   ret void
 }
 
-; Check sprintf(dst, "%s", str) -> llvm.memcpy(dest, str, strlen(str) + 1, 1).
+; Check sprintf(dst, "%s", str) -> strcpy(dst, "%s", str) if result is unused.
 
 define void @test_simplify5(i8* %dst, i8* %str) {
 ; CHECK-LABEL: @test_simplify5(
-; CHECK-NEXT:    [[STRLEN:%.*]] = call i32 @strlen(i8* nonnull dereferenceable(1) [[STR:%.*]])
-; CHECK-NEXT:    [[LENINC:%.*]] = add i32 [[STRLEN]], 1
-; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 1 [[DST:%.*]], i8* align 1 [[STR]], i32 [[LENINC]], i1 false)
+; CHECK-NEXT:    [[STRCPY:%.*]] = call i8* @strcpy(i8* nonnull dereferenceable(1) [[DST:%.*]], i8* nonnull dereferenceable(1) [[STR:%.*]])
 ; CHECK-NEXT:    ret void
 ;
 ; CHECK-IPRINTF-LABEL: @test_simplify5(
-; CHECK-IPRINTF-NEXT:    [[STRLEN:%.*]] = call i32 @strlen(i8* nonnull dereferenceable(1) [[STR:%.*]])
-; CHECK-IPRINTF-NEXT:    [[LENINC:%.*]] = add i32 [[STRLEN]], 1
-; CHECK-IPRINTF-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 1 [[DST:%.*]], i8* align 1 [[STR]], i32 [[LENINC]], i1 false)
+; CHECK-IPRINTF-NEXT:    [[STRCPY:%.*]] = call i8* @strcpy(i8* nonnull dereferenceable(1) [[DST:%.*]], i8* nonnull dereferenceable(1) [[STR:%.*]])
 ; CHECK-IPRINTF-NEXT:    ret void
 ;
   %fmt = getelementptr [3 x i8], [3 x i8]* @percent_s, i32 0, i32 0
@@ -117,6 +113,26 @@
   ret void
 }
 
+; Check sprintf(dst, "%s", str) -> llvm.memcpy(dest, str, strlen(str) + 1, 1).
+
+define i32 @test_simplify7(i8* %dst, i8* %str) {
+; CHECK-LABEL: @test_simplify7(
+; CHECK-NEXT:    [[STRLEN:%.*]] = call i32 @strlen(i8* nonnull dereferenceable(1) [[STR:%.*]])
+; CHECK-NEXT:    [[LENINC:%.*]] = add i32 [[STRLEN]], 1
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 1 [[DST:%.*]], i8* align 1 [[STR]], i32 [[LENINC]], i1 false)
+; CHECK-NEXT:    ret i32 [[STRLEN]]
+;
+; CHECK-IPRINTF-LABEL: @test_simplify7(
+; CHECK-IPRINTF-NEXT:    [[STRLEN:%.*]] = call i32 @strlen(i8* nonnull dereferenceable(1) [[STR:%.*]])
+; CHECK-IPRINTF-NEXT:    [[LENINC:%.*]] = add i32 [[STRLEN]], 1
+; CHECK-IPRINTF-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 1 [[DST:%.*]], i8* align 1 [[STR]], i32 [[LENINC]], i1 false)
+; CHECK-IPRINTF-NEXT:    ret i32 [[STRLEN]]
+;
+  %fmt = getelementptr [3 x i8], [3 x i8]* @percent_s, i32 0, i32 0
+  %r = call i32 (i8*, i8*, ...) @sprintf(i8* %dst, i8* %fmt, i8* %str)
+  ret i32 %r
+}
+
 define void @test_no_simplify1(i8* %dst) {
 ; CHECK-LABEL: @test_no_simplify1(
 ; CHECK-NEXT:    [[TMP1:%.*]] = call i32 (i8*, i8*, ...) @sprintf(i8* nonnull dereferenceable(1) [[DST:%.*]], i8* nonnull dereferenceable(1) getelementptr inbounds ([3 x i8], [3 x i8]* @percent_f, i32 0, i32 0), double 1.870000e+00)
@@ -143,3 +159,17 @@
   call i32 (i8*, i8*, ...) @sprintf(i8* %dst, i8* %fmt, double %d)
   ret void
 }
+
+define i32 @test_no_simplify3(i8* %dst, i8* %str) minsize {
+; CHECK-LABEL: @test_no_simplify3(
+; CHECK-NEXT:    [[R:%.*]] = call i32 (i8*, i8*, ...) @sprintf(i8* nonnull dereferenceable(1) [[DST:%.*]], i8* nonnull dereferenceable(1) getelementptr inbounds ([3 x i8], [3 x i8]* @percent_s, i32 0, i32 0), i8* [[STR:%.*]])
+; CHECK-NEXT:    ret i32 [[R]]
+;
+; CHECK-IPRINTF-LABEL: @test_no_simplify3(
+; CHECK-IPRINTF-NEXT:    [[TMP1:%.*]] = call i32 (i8*, i8*, ...) @siprintf(i8* [[DST:%.*]], i8* getelementptr inbounds ([3 x i8], [3 x i8]* @percent_s, i32 0, i32 0), i8* [[STR:%.*]])
+; CHECK-IPRINTF-NEXT:    ret i32 [[TMP1]]
+;
+  %fmt = getelementptr [3 x i8], [3 x i8]* @percent_s, i32 0, i32 0
+  %r = call i32 (i8*, i8*, ...) @sprintf(i8* %dst, i8* %fmt, i8* %str)
+  ret i32 %r
+}