instcombine: Migrate strcpy optimizations

This patch migrates the strcpy optimizations from the simplify-libcalls pass
into the instcombine library call simplifier.  Note also that StrCpyChkOpt
has been updated with a few simplifications that were being done in the
simplify-libcalls version of StrCpyOpt, but not in the migrated implementation
of StrCpyOpt.  There is no reason to overload StrCpyOpt with fortified and
regular simplifications in the new model since there is already a dedicated
simplifier for __strcpy_chk.

llvm-svn: 166198

1 files changed, 30 insertions, 24 deletions

diff --git a/llvm/test/Transforms/InstCombine/strcpy_chk-1.ll b/llvm/test/Transforms/InstCombine/strcpy_chk-1.ll
index c03e8a348b8..3e48f4fd305 100644
--- a/llvm/test/Transforms/InstCombine/strcpy_chk-1.ll
+++ b/llvm/test/Transforms/InstCombine/strcpy_chk-1.ll
@@ -7,16 +7,16 @@ target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f3
 
 @a = common global [60 x i8] zeroinitializer, align 1
 @b = common global [60 x i8] zeroinitializer, align 1
-@.str = private constant [8 x i8] c"abcdefg\00"
+@.str = private constant [12 x i8] c"abcdefghijk\00"
 
 ; Check cases where slen >= strlen (src).
 
 define void @test_simplify1() {
 ; CHECK: @test_simplify1
   %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0
-  %src = getelementptr inbounds [8 x i8]* @.str, i32 0, i32 0
+  %src = getelementptr inbounds [12 x i8]* @.str, i32 0, i32 0
 
-; CHECK-NEXT: call i8* @strcpy
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32
   call i8* @__strcpy_chk(i8* %dst, i8* %src, i32 60)
   ret void
 }
@@ -24,19 +24,19 @@ define void @test_simplify1() {
 define void @test_simplify2() {
 ; CHECK: @test_simplify2
   %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0
-  %src = getelementptr inbounds [8 x i8]* @.str, i32 0, i32 0
+  %src = getelementptr inbounds [12 x i8]* @.str, i32 0, i32 0
 
-; CHECK-NEXT: call i8* @strcpy
-  call i8* @__strcpy_chk(i8* %dst, i8* %src, i32 8)
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32
+  call i8* @__strcpy_chk(i8* %dst, i8* %src, i32 12)
   ret void
 }
 
 define void @test_simplify3() {
 ; CHECK: @test_simplify3
   %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0
-  %src = getelementptr inbounds [8 x i8]* @.str, i32 0, i32 0
+  %src = getelementptr inbounds [12 x i8]* @.str, i32 0, i32 0
 
-; CHECK-NEXT: call i8* @strcpy
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32
   call i8* @__strcpy_chk(i8* %dst, i8* %src, i32 -1)
   ret void
 }
@@ -53,36 +53,42 @@ define void @test_simplify4() {
   ret void
 }
 
-define void @test_no_simplify1() {
-; CHECK: @test_no_simplify1
+; Check case where the string length is not constant.
+
+define void @test_simplify5() {
+; CHECK: @test_simplify5
   %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0
-  %src = getelementptr inbounds [60 x i8]* @b, i32 0, i32 0
+  %src = getelementptr inbounds [12 x i8]* @.str, i32 0, i32 0
 
-; CHECK-NEXT: call i8* @__strcpy_chk
-  call i8* @__strcpy_chk(i8* %dst, i8* %src, i32 8)
+; CHECK: @__memcpy_chk
+  %len = call i32 @llvm.objectsize.i32(i8* %dst, i1 false)
+  call i8* @__strcpy_chk(i8* %dst, i8* %src, i32 %len)
   ret void
 }
 
-; Check case were slen < strlen (src).
+; Check case where the source and destination are the same.
 
-define void @test_no_simplify2() {
-; CHECK: @test_no_simplify2
+define i8* @test_simplify6() {
+; CHECK: @test_simplify6
   %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0
-  %src = getelementptr inbounds [8 x i8]* @.str, i32 0, i32 0
 
-; CHECK-NEXT: call i8* @__strcpy_chk
-  call i8* @__strcpy_chk(i8* %dst, i8* %src, i32 3)
-  ret void
+; CHECK: getelementptr inbounds ([60 x i8]* @a, i32 0, i32 0)
+  %len = call i32 @llvm.objectsize.i32(i8* %dst, i1 false)
+  %ret = call i8* @__strcpy_chk(i8* %dst, i8* %dst, i32 %len)
+  ret i8* %ret
 }
 
-define void @test_no_simplify3() {
-; CHECK: @test_no_simplify3
+; Check case where slen < strlen (src).
+
+define void @test_no_simplify1() {
+; CHECK: @test_no_simplify1
   %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0
-  %src = getelementptr inbounds [8 x i8]* @.str, i32 0, i32 0
+  %src = getelementptr inbounds [60 x i8]* @b, i32 0, i32 0
 
 ; CHECK-NEXT: call i8* @__strcpy_chk
-  call i8* @__strcpy_chk(i8* %dst, i8* %src, i32 0)
+  call i8* @__strcpy_chk(i8* %dst, i8* %src, i32 8)
   ret void
 }
 
 declare i8* @__strcpy_chk(i8*, i8*, i32) nounwind
+declare i32 @llvm.objectsize.i32(i8*, i1) nounwind readonly