instcombine: Migrate strcat and strncat optimizations

This patch migrates the strcat and strncat optimizations from the
simplify-libcalls pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165874 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 204 insertions, 0 deletions

diff --git a/test/Transforms/InstCombine/strcat-1.ll b/test/Transforms/InstCombine/strcat-1.ll
new file mode 100644
index 0000000000..3c05d6b06f
--- /dev/null
+++ b/test/Transforms/InstCombine/strcat-1.ll
@@ -0,0 +1,38 @@
+; Test that the strcat libcall simplifier works correctly per the
+; bug found in PR3661.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+@hello = constant [6 x i8] c"hello\00"
+@null = constant [1 x i8] zeroinitializer
+@null_hello = constant [7 x i8] c"\00hello\00"
+
+declare i8* @strcat(i8*, i8*)
+declare i32 @puts(i8*)
+
+define i32 @main() {
+; CHECK: @main
+; CHECK-NOT: call i8* @strcat
+; CHECK: call i32 @puts
+
+  %target = alloca [1024 x i8]
+  %arg1 = getelementptr [1024 x i8]* %target, i32 0, i32 0
+  store i8 0, i8* %arg1
+
+  ; rslt1 = strcat(target, "hello\00")
+  %arg2 = getelementptr [6 x i8]* @hello, i32 0, i32 0
+  %rslt1 = call i8* @strcat(i8* %arg1, i8* %arg2)
+
+  ; rslt2 = strcat(rslt1, "\00")
+  %arg3 = getelementptr [1 x i8]* @null, i32 0, i32 0
+  %rslt2 = call i8* @strcat(i8* %rslt1, i8* %arg3)
+
+  ; rslt3 = strcat(rslt2, "\00hello\00")
+  %arg4 = getelementptr [7 x i8]* @null_hello, i32 0, i32 0
+  %rslt3 = call i8* @strcat(i8* %rslt2, i8* %arg4)
+
+  call i32 @puts( i8* %rslt3 )
+  ret i32 0
+}
diff --git a/test/Transforms/InstCombine/strcat-2.ll b/test/Transforms/InstCombine/strcat-2.ll
new file mode 100644
index 0000000000..379ee74953
--- /dev/null
+++ b/test/Transforms/InstCombine/strcat-2.ll
@@ -0,0 +1,32 @@
+; Test that the strcat libcall simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+@hello = constant [6 x i8] c"hello\00"
+@empty = constant [1 x i8] c"\00"
+@a = common global [32 x i8] zeroinitializer, align 1
+
+declare i8* @strcat(i8*, i8*)
+
+define void @test_simplify1() {
+; CHECK: @test_simplify1
+; CHECK-NOT: call i8* @strcat
+; CHECK: ret void
+
+  %dst = getelementptr [32 x i8]* @a, i32 0, i32 0
+  %src = getelementptr [6 x i8]* @hello, i32 0, i32 0
+  call i8* @strcat(i8* %dst, i8* %src)
+  ret void
+}
+
+define void @test_simplify2() {
+; CHECK: @test_simplify2
+; CHECK-NEXT: ret void
+
+  %dst = getelementptr [32 x i8]* @a, i32 0, i32 0
+  %src = getelementptr [1 x i8]* @empty, i32 0, i32 0
+  call i8* @strcat(i8* %dst, i8* %src)
+  ret void
+}
diff --git a/test/Transforms/InstCombine/strcat-3.ll b/test/Transforms/InstCombine/strcat-3.ll
new file mode 100644
index 0000000000..15aff2f1aa
--- /dev/null
+++ b/test/Transforms/InstCombine/strcat-3.ll
@@ -0,0 +1,22 @@
+; Test that the strcat libcall simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+@hello = constant [6 x i8] c"hello\00"
+@empty = constant [1 x i8] c"\00"
+@a = common global [32 x i8] zeroinitializer, align 1
+
+declare i16* @strcat(i8*, i8*)
+
+define void @test_nosimplify1() {
+; CHECK: @test_nosimplify1
+; CHECK: call i16* @strcat
+; CHECK: ret void
+
+  %dst = getelementptr [32 x i8]* @a, i32 0, i32 0
+  %src = getelementptr [6 x i8]* @hello, i32 0, i32 0
+  call i16* @strcat(i8* %dst, i8* %src)
+  ret void
+}
diff --git a/test/Transforms/InstCombine/strncat-1.ll b/test/Transforms/InstCombine/strncat-1.ll
new file mode 100644
index 0000000000..ad2a18b146
--- /dev/null
+++ b/test/Transforms/InstCombine/strncat-1.ll
@@ -0,0 +1,37 @@
+; Test that the strncat libcall simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+@hello = constant [6 x i8] c"hello\00"
+@null = constant [1 x i8] zeroinitializer
+@null_hello = constant [7 x i8] c"\00hello\00"
+
+declare i8* @strncat(i8*, i8*, i32)
+declare i32 @puts(i8*)
+
+define i32 @main() {
+; CHECK: @main
+; CHECK-NOT: call i8* @strncat
+; CHECK: call i32 @puts
+
+  %target = alloca [1024 x i8]
+  %arg1 = getelementptr [1024 x i8]* %target, i32 0, i32 0
+  store i8 0, i8* %arg1
+
+  ; rslt1 = strncat(target, "hello\00")
+  %arg2 = getelementptr [6 x i8]* @hello, i32 0, i32 0
+  %rslt1 = call i8* @strncat(i8* %arg1, i8* %arg2, i32 6)
+
+  ; rslt2 = strncat(rslt1, "\00")
+  %arg3 = getelementptr [1 x i8]* @null, i32 0, i32 0
+  %rslt2 = call i8* @strncat(i8* %rslt1, i8* %arg3, i32 42)
+
+  ; rslt3 = strncat(rslt2, "\00hello\00")
+  %arg4 = getelementptr [7 x i8]* @null_hello, i32 0, i32 0
+  %rslt3 = call i8* @strncat(i8* %rslt2, i8* %arg4, i32 42)
+
+  call i32 @puts(i8* %rslt3)
+  ret i32 0
+}
diff --git a/test/Transforms/InstCombine/strncat-2.ll b/test/Transforms/InstCombine/strncat-2.ll
new file mode 100644
index 0000000000..c56deacd39
--- /dev/null
+++ b/test/Transforms/InstCombine/strncat-2.ll
@@ -0,0 +1,53 @@
+; Test that the strncat libcall simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+@hello = constant [6 x i8] c"hello\00"
+@empty = constant [1 x i8] c"\00"
+@a = common global [32 x i8] zeroinitializer, align 1
+
+declare i8* @strncat(i8*, i8*, i32)
+
+define void @test_simplify1() {
+; CHECK: @test_simplify1
+; CHECK-NOT: call i8* @strncat
+; CHECK: ret void
+
+  %dst = getelementptr [32 x i8]* @a, i32 0, i32 0
+  %src = getelementptr [6 x i8]* @hello, i32 0, i32 0
+  call i8* @strncat(i8* %dst, i8* %src, i32 13)
+  ret void
+}
+
+define void @test_simplify2() {
+; CHECK: @test_simplify2
+; CHECK-NEXT: ret void
+
+  %dst = getelementptr [32 x i8]* @a, i32 0, i32 0
+  %src = getelementptr [1 x i8]* @empty, i32 0, i32 0
+  call i8* @strncat(i8* %dst, i8* %src, i32 13)
+  ret void
+}
+
+define void @test_simplify3() {
+; CHECK: @test_simplify3
+; CHECK-NEXT: ret void
+
+  %dst = getelementptr [32 x i8]* @a, i32 0, i32 0
+  %src = getelementptr [6 x i8]* @hello, i32 0, i32 0
+  call i8* @strncat(i8* %dst, i8* %src, i32 0)
+  ret void
+}
+
+define void @test_nosimplify1() {
+; CHECK: @test_nosimplify1
+; CHECK: call i8* @strncat
+; CHECK: ret void
+
+  %dst = getelementptr [32 x i8]* @a, i32 0, i32 0
+  %src = getelementptr [6 x i8]* @hello, i32 0, i32 0
+  call i8* @strncat(i8* %dst, i8* %src, i32 1)
+  ret void
+}
diff --git a/test/Transforms/InstCombine/strncat-3.ll b/test/Transforms/InstCombine/strncat-3.ll
new file mode 100644
index 0000000000..3cd7971687
--- /dev/null
+++ b/test/Transforms/InstCombine/strncat-3.ll
@@ -0,0 +1,22 @@
+; Test that the strncat libcall simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+@hello = constant [6 x i8] c"hello\00"
+@empty = constant [1 x i8] c"\00"
+@a = common global [32 x i8] zeroinitializer, align 1
+
+declare i16* @strncat(i8*, i8*, i32)
+
+define void @test_nosimplify1() {
+; CHECK: @test_nosimplify1
+; CHECK: call i16* @strncat
+; CHECK: ret void
+
+  %dst = getelementptr [32 x i8]* @a, i32 0, i32 0
+  %src = getelementptr [6 x i8]* @hello, i32 0, i32 0
+  call i16* @strncat(i8* %dst, i8* %src, i32 13)
+  ret void
+}