instcombine: Migrate strcmp and strncmp optimizations

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165915 91177308-0d34-0410-b5e6-96231b3b80d8

8 files changed, 252 insertions, 169 deletions

diff --git a/test/Transforms/InstCombine/strcmp-1.ll b/test/Transforms/InstCombine/strcmp-1.ll
new file mode 100644
index 0000000000..0679246e09
--- /dev/null
+++ b/test/Transforms/InstCombine/strcmp-1.ll
@@ -0,0 +1,82 @@
+; Test that the strcmp library call 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"
+@hell = constant [5 x i8] c"hell\00"
+@bell = constant [5 x i8] c"bell\00"
+@null = constant [1 x i8] zeroinitializer
+
+declare i32 @strcmp(i8*, i8*)
+
+; strcmp("", x) -> -*x
+define i32 @test1(i8* %str2) {
+; CHECK: @test1
+; CHECK: %strcmpload = load i8* %str
+; CHECK: %1 = zext i8 %strcmpload to i32
+; CHECK: %2 = sub i32 0, %1
+; CHECK: ret i32 %2
+
+  %str1 = getelementptr inbounds [1 x i8]* @null, i32 0, i32 0
+  %temp1 = call i32 @strcmp(i8* %str1, i8* %str2)
+  ret i32 %temp1
+
+}
+
+; strcmp(x, "") -> *x
+define i32 @test2(i8* %str1) {
+; CHECK: @test2
+; CHECK: %strcmpload = load i8* %str
+; CHECK: %1 = zext i8 %strcmpload to i32
+; CHECK: ret i32 %1
+
+  %str2 = getelementptr inbounds [1 x i8]* @null, i32 0, i32 0
+  %temp1 = call i32 @strcmp(i8* %str1, i8* %str2)
+  ret i32 %temp1
+}
+
+; strcmp(x, y)  -> cnst
+define i32 @test3() {
+; CHECK: @test3
+; CHECK: ret i32 -1
+
+  %str1 = getelementptr inbounds [5 x i8]* @hell, i32 0, i32 0
+  %str2 = getelementptr inbounds [6 x i8]* @hello, i32 0, i32 0
+  %temp1 = call i32 @strcmp(i8* %str1, i8* %str2)
+  ret i32 %temp1
+}
+
+define i32 @test4() {
+; CHECK: @test4
+; CHECK: ret i32 1
+
+  %str1 = getelementptr inbounds [5 x i8]* @hell, i32 0, i32 0
+  %str2 = getelementptr inbounds [1 x i8]* @null, i32 0, i32 0
+  %temp1 = call i32 @strcmp(i8* %str1, i8* %str2)
+  ret i32 %temp1
+}
+
+; strcmp(x, y)   -> memcmp(x, y, <known length>)
+; (This transform is rather difficult to trigger in a useful manner)
+define i32 @test5(i1 %b) {
+; CHECK: @test5
+; CHECK: %memcmp = call i32 @memcmp(i8* getelementptr inbounds ([6 x i8]* @hello, i32 0, i32 0), i8* %str2, i32 5)
+; CHECK: ret i32 %memcmp
+
+  %str1 = getelementptr inbounds [6 x i8]* @hello, i32 0, i32 0
+  %temp1 = getelementptr inbounds [5 x i8]* @hell, i32 0, i32 0
+  %temp2 = getelementptr inbounds [5 x i8]* @bell, i32 0, i32 0
+  %str2 = select i1 %b, i8* %temp1, i8* %temp2
+  %temp3 = call i32 @strcmp(i8* %str1, i8* %str2)
+  ret i32 %temp3
+}
+
+; strcmp(x,x)  -> 0
+define i32 @test6(i8* %str) {
+; CHECK: @test6
+; CHECK: ret i32 0
+
+  %temp1 = call i32 @strcmp(i8* %str, i8* %str)
+  ret i32 %temp1
+}
diff --git a/test/Transforms/InstCombine/strcmp-2.ll b/test/Transforms/InstCombine/strcmp-2.ll
new file mode 100644
index 0000000000..20518960f3
--- /dev/null
+++ b/test/Transforms/InstCombine/strcmp-2.ll
@@ -0,0 +1,20 @@
+; Test that the strcmp library call 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"
+@hell = constant [5 x i8] c"hell\00"
+
+declare i16 @strcmp(i8*, i8*)
+
+define i16 @test_nosimplify() {
+; CHECK: @test_nosimplify
+; CHECK: call i16 @strcmp
+; CHECK: ret i16 %temp1
+
+  %str1 = getelementptr inbounds [5 x i8]* @hell, i32 0, i32 0
+  %str2 = getelementptr inbounds [6 x i8]* @hello, i32 0, i32 0
+  %temp1 = call i16 @strcmp(i8* %str1, i8* %str2)
+  ret i16 %temp1
+}
diff --git a/test/Transforms/InstCombine/strncmp-1.ll b/test/Transforms/InstCombine/strncmp-1.ll
new file mode 100644
index 0000000000..48b26d1a5f
--- /dev/null
+++ b/test/Transforms/InstCombine/strncmp-1.ll
@@ -0,0 +1,97 @@
+; Test that the strncmp library call 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"
+@hell = constant [5 x i8] c"hell\00"
+@bell = constant [5 x i8] c"bell\00"
+@null = constant [1 x i8] zeroinitializer
+
+declare i32 @strncmp(i8*, i8*, i32)
+
+; strncmp("", x, n) -> -*x
+define i32 @test1(i8* %str2) {
+; CHECK: @test1
+; CHECK: %strcmpload = load i8* %str
+; CHECK: %1 = zext i8 %strcmpload to i32
+; CHECK: %2 = sub i32 0, %1
+; CHECK: ret i32 %2
+
+  %str1 = getelementptr inbounds [1 x i8]* @null, i32 0, i32 0
+  %temp1 = call i32 @strncmp(i8* %str1, i8* %str2, i32 10)
+  ret i32 %temp1
+}
+
+; strncmp(x, "", n) -> *x
+define i32 @test2(i8* %str1) {
+; CHECK: @test2
+; CHECK: %strcmpload = load i8* %str1
+; CHECK: %1 = zext i8 %strcmpload to i32
+; CHECK: ret i32 %1
+
+  %str2 = getelementptr inbounds [1 x i8]* @null, i32 0, i32 0
+  %temp1 = call i32 @strncmp(i8* %str1, i8* %str2, i32 10)
+  ret i32 %temp1
+}
+
+; strncmp(x, y, n)  -> cnst
+define i32 @test3() {
+; CHECK: @test3
+; CHECK: ret i32 -1
+
+  %str1 = getelementptr inbounds [5 x i8]* @hell, i32 0, i32 0
+  %str2 = getelementptr inbounds [6 x i8]* @hello, i32 0, i32 0
+  %temp1 = call i32 @strncmp(i8* %str1, i8* %str2, i32 10)
+  ret i32 %temp1
+}
+
+define i32 @test4() {
+; CHECK: @test4
+; CHECK: ret i32 1
+
+  %str1 = getelementptr inbounds [5 x i8]* @hell, i32 0, i32 0
+  %str2 = getelementptr inbounds [1 x i8]* @null, i32 0, i32 0
+  %temp1 = call i32 @strncmp(i8* %str1, i8* %str2, i32 10)
+  ret i32 %temp1
+}
+
+define i32 @test5() {
+; CHECK: @test5
+; CHECK: ret i32 0
+
+  %str1 = getelementptr inbounds [5 x i8]* @hell, i32 0, i32 0
+  %str2 = getelementptr inbounds [6 x i8]* @hello, i32 0, i32 0
+  %temp1 = call i32 @strncmp(i8* %str1, i8* %str2, i32 4)
+  ret i32 %temp1
+}
+
+; strncmp(x,y,1) -> memcmp(x,y,1)
+; TODO: Once the memcmp simplifier gets moved into the instcombine pass
+; the following memcmp will be folded into two loads and a subtract.
+define i32 @test6(i8* %str1, i8* %str2) {
+; CHECK: @test6
+; CHECK: call i32 @memcmp
+; CHECK: ret i32 %memcmp
+
+  %temp1 = call i32 @strncmp(i8* %str1, i8* %str2, i32 1)
+  ret i32 %temp1
+}
+
+; strncmp(x,y,0)   -> 0
+define i32 @test7(i8* %str1, i8* %str2) {
+; CHECK: @test7
+; CHECK: ret i32 0
+
+  %temp1 = call i32 @strncmp(i8* %str1, i8* %str2, i32 0)
+  ret i32 %temp1
+}
+
+; strncmp(x,x,n)  -> 0
+define i32 @test8(i8* %str, i32 %n) {
+; CHECK: @test8
+; CHECK: ret i32 0
+
+  %temp1 = call i32 @strncmp(i8* %str, i8* %str, i32 %n)
+  ret i32 %temp1
+}
diff --git a/test/Transforms/InstCombine/strncmp-2.ll b/test/Transforms/InstCombine/strncmp-2.ll
new file mode 100644
index 0000000000..3fc43a6fd4
--- /dev/null
+++ b/test/Transforms/InstCombine/strncmp-2.ll
@@ -0,0 +1,20 @@
+; Test that the strncmp library call 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"
+@hell = constant [5 x i8] c"hell\00"
+
+declare i16 @strncmp(i8*, i8*, i32)
+
+define i16 @test_nosimplify() {
+; CHECK: @test_nosimplify
+; CHECK: call i16 @strncmp
+; CHECK: ret i16 %temp1
+
+  %str1 = getelementptr inbounds [5 x i8]* @hell, i32 0, i32 0
+  %str2 = getelementptr inbounds [6 x i8]* @hello, i32 0, i32 0
+  %temp1 = call i16 @strncmp(i8* %str1, i8* %str2, i32 10)
+  ret i16 %temp1
+}
diff --git a/test/Transforms/InstCombine/weak-symbols.ll b/test/Transforms/InstCombine/weak-symbols.ll
new file mode 100644
index 0000000000..0039b5962f
--- /dev/null
+++ b/test/Transforms/InstCombine/weak-symbols.ll
@@ -0,0 +1,33 @@
+; PR4738 - Test that the library call simplifier doesn't assume anything about
+; weak symbols.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+@real_init = weak_odr constant [2 x i8] c"y\00"
+@fake_init = weak constant [2 x i8] c"y\00"
+@.str = private constant [2 x i8] c"y\00"
+
+define i32 @foo() nounwind {
+; CHECK: define i32 @foo
+; CHECK: call i32 @strcmp
+; CHECK: ret i32 %temp1
+
+entry:
+  %str1 = getelementptr inbounds [2 x i8]* @fake_init, i64 0, i64 0
+  %str2 = getelementptr inbounds [2 x i8]* @.str, i64 0, i64 0
+  %temp1 = call i32 @strcmp(i8* %str1, i8* %str2) nounwind readonly
+  ret i32 %temp1
+}
+
+define i32 @bar() nounwind {
+; CHECK: define i32 @bar
+; CHECK: ret i32 0
+
+entry:
+  %str1 = getelementptr inbounds [2 x i8]* @real_init, i64 0, i64 0
+  %str2 = getelementptr inbounds [2 x i8]* @.str, i64 0, i64 0
+  %temp1 = call i32 @strcmp(i8* %str1, i8* %str2) nounwind readonly
+  ret i32 %temp1
+}
+
+declare i32 @strcmp(i8*, i8*) nounwind readonly
diff --git a/test/Transforms/SimplifyLibCalls/StrCmp.ll b/test/Transforms/SimplifyLibCalls/StrCmp.ll
deleted file mode 100644
index 60854d76c9..0000000000
--- a/test/Transforms/SimplifyLibCalls/StrCmp.ll
+++ /dev/null
@@ -1,65 +0,0 @@
-; Test that the StrCmpOptimizer works correctly
-; RUN: opt < %s -simplify-libcalls -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"		; <[6 x i8]*> [#uses=1]
-@hell = constant [5 x i8] c"hell\00"		; <[5 x i8]*> [#uses=1]
-@bell = constant [5 x i8] c"bell\00"		; <[5 x i8]*> [#uses=1]
-@null = constant [1 x i8] zeroinitializer		; <[1 x i8]*> [#uses=1]
-
-declare i32 @strcmp(i8*, i8*)
-
-; strcmp("", x) -> -*x
-define i32 @test1(i8* %str) {
-  %temp1 = call i32 @strcmp(i8* getelementptr inbounds ([1 x i8]* @null, i32 0, i32 0), i8* %str)
-  ret i32 %temp1
-  ; CHECK: @test1
-  ; CHECK: %strcmpload = load i8* %str
-  ; CHECK: %1 = zext i8 %strcmpload to i32
-  ; CHECK: %temp1 = sub i32 0, %1
-  ; CHECK: ret i32 %temp1
-}
-
-; strcmp(x, "") -> *x
-define i32 @test2(i8* %str) {
-  %temp1 = call i32 @strcmp(i8* %str, i8* getelementptr inbounds ([1 x i8]* @null, i32 0, i32 0))
-  ret i32 %temp1
-  ; CHECK: @test2
-  ; CHECK: %strcmpload = load i8* %str
-  ; CHECK: %temp1 = zext i8 %strcmpload to i32
-  ; CHECK: ret i32 %temp1
-}
-
-; strcmp(x, y)  -> cnst
-define i32 @test3() {
-  %temp1 = call i32 @strcmp(i8* getelementptr inbounds ([5 x i8]* @hell, i32 0, i32 0), i8* getelementptr inbounds ([6 x i8]* @hello, i32 0, i32 0))
-  ret i32 %temp1
-  ; CHECK: @test3
-  ; CHECK: ret i32 -1
-}
-define i32 @test4() {
-  %temp1 = call i32 @strcmp(i8* getelementptr inbounds ([5 x i8]* @hell, i32 0, i32 0), i8* getelementptr inbounds ([1 x i8]* @null, i32 0, i32 0))
-  ret i32 %temp1
-  ; CHECK: @test4
-  ; CHECK: ret i32 1
-}
-
-; strcmp(x, y)   -> memcmp(x, y, <known length>)
-; (This transform is rather difficult to trigger in a useful manner)
-define i32 @test5(i1 %b) {
-  %sel = select i1 %b, i8* getelementptr inbounds ([5 x i8]* @hell, i32 0, i32 0), i8* getelementptr inbounds ([5 x i8]* @bell, i32 0, i32 0)
-  %temp1 = call i32 @strcmp(i8* getelementptr inbounds ([6 x i8]* @hello, i32 0, i32 0), i8* %sel)
-  ret i32 %temp1
-  ; CHECK: @test5
-  ; CHECK: %memcmp = call i32 @memcmp(i8* getelementptr inbounds ([6 x i8]* @hello, i32 0, i32 0), i8* %sel, i32 5)
-  ; CHECK: ret i32 %memcmp
-}
-
-; strcmp(x,x)  -> 0
-define i32 @test6(i8* %str) {
-  %temp1 = call i32 @strcmp(i8* %str, i8* %str)
-  ret i32 %temp1
-  ; CHECK: @test6
-  ; CHECK: ret i32 0
-}
diff --git a/test/Transforms/SimplifyLibCalls/StrNCmp.ll b/test/Transforms/SimplifyLibCalls/StrNCmp.ll
deleted file mode 100644
index 0b2a501a3c..0000000000
--- a/test/Transforms/SimplifyLibCalls/StrNCmp.ll
+++ /dev/null
@@ -1,78 +0,0 @@
-; Test that the StrCmpOptimizer works correctly
-; RUN: opt < %s -simplify-libcalls -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"		; <[6 x i8]*> [#uses=1]
-@hell = constant [5 x i8] c"hell\00"		; <[5 x i8]*> [#uses=1]
-@bell = constant [5 x i8] c"bell\00"		; <[5 x i8]*> [#uses=1]
-@null = constant [1 x i8] zeroinitializer		; <[1 x i8]*> [#uses=1]
-
-declare i32 @strncmp(i8*, i8*, i32)
-
-; strcmp("", x) -> -*x
-define i32 @test1(i8* %str) {
-  %temp1 = call i32 @strncmp(i8* getelementptr inbounds ([1 x i8]* @null, i32 0, i32 0), i8* %str, i32 10)
-  ret i32 %temp1
-  ; CHECK: @test1
-  ; CHECK: %strcmpload = load i8* %str
-  ; CHECK: %1 = zext i8 %strcmpload to i32
-  ; CHECK: %temp1 = sub i32 0, %1
-  ; CHECK: ret i32 %temp1
-}
-
-; strcmp(x, "") -> *x
-define i32 @test2(i8* %str) {
-  %temp1 = call i32 @strncmp(i8* %str, i8* getelementptr inbounds ([1 x i8]* @null, i32 0, i32 0), i32 10)
-  ret i32 %temp1
-  ; CHECK: @test2
-  ; CHECK: %strcmpload = load i8* %str
-  ; CHECK: %temp1 = zext i8 %strcmpload to i32
-  ; CHECK: ret i32 %temp1
-}
-
-; strncmp(x, y, n)  -> cnst
-define i32 @test3() {
-  %temp1 = call i32 @strncmp(i8* getelementptr inbounds ([5 x i8]* @hell, i32 0, i32 0), i8* getelementptr inbounds ([6 x i8]* @hello, i32 0, i32 0), i32 10)
-  ret i32 %temp1
-  ; CHECK: @test3
-  ; CHECK: ret i32 -1
-}
-define i32 @test4() {
-  %temp1 = call i32 @strncmp(i8* getelementptr inbounds ([5 x i8]* @hell, i32 0, i32 0), i8* getelementptr inbounds ([1 x i8]* @null, i32 0, i32 0), i32 10)
-  ret i32 %temp1
-  ; CHECK: @test4
-  ; CHECK: ret i32 1
-}
-define i32 @test5() {
-  %temp1 = call i32 @strncmp(i8* getelementptr inbounds ([5 x i8]* @hell, i32 0, i32 0), i8* getelementptr inbounds ([6 x i8]* @hello, i32 0, i32 0), i32 4)
-  ret i32 %temp1
-  ; CHECK: @test5
-  ; CHECK: ret i32 0
-}
-
-; strncmp(x,y,1) -> memcmp(x,y,1)
-define i32 @test6(i8* %str1, i8* %str2) {
-  %temp1 = call i32 @strncmp(i8* %str1, i8* %str2, i32 1)
-  ret i32 %temp1
-  ; CHECK: @test6
-  ; CHECK: load i8*
-  ; CHECK: load i8*
-  ; CHECK: sub i32
-}
-
-; strncmp(x,y,0)   -> 0
-define i32 @test7(i8* %str1, i8* %str2) {
-  %temp1 = call i32 @strncmp(i8* %str1, i8* %str2, i32 0)
-  ret i32 %temp1
-  ; CHECK: @test7
-  ; CHECK: ret i32 0
-}
-
-; strncmp(x,x,n)  -> 0
-define i32 @test8(i8* %str, i32 %n) {
-  %temp1 = call i32 @strncmp(i8* %str, i8* %str, i32 %n)
-  ret i32 %temp1
-  ; CHECK: @test8
-  ; CHECK: ret i32 0
-}
diff --git a/test/Transforms/SimplifyLibCalls/weak-symbols.ll b/test/Transforms/SimplifyLibCalls/weak-symbols.ll
deleted file mode 100644
index 5875b211f7..0000000000
--- a/test/Transforms/SimplifyLibCalls/weak-symbols.ll
+++ /dev/null
@@ -1,26 +0,0 @@
-; RUN: opt < %s -simplify-libcalls -S | FileCheck %s
-; PR4738
-
-; SimplifyLibcalls shouldn't assume anything about weak symbols.
-
-@real_init = weak_odr constant [2 x i8] c"y\00"
-@fake_init = weak constant [2 x i8] c"y\00"
-@.str = private constant [2 x i8] c"y\00"
-
-; CHECK: define i32 @foo
-; CHECK: call i32 @strcmp
-define i32 @foo() nounwind {
-entry:
-  %t0 = call i32 @strcmp(i8* getelementptr inbounds ([2 x i8]* @fake_init, i64 0, i64 0), i8* getelementptr inbounds ([2 x i8]* @.str, i64 0, i64 0)) nounwind readonly
-  ret i32 %t0
-}
-
-; CHECK: define i32 @bar
-; CHECK: ret i32 0
-define i32 @bar() nounwind {
-entry:
-  %t0 = call i32 @strcmp(i8* getelementptr inbounds ([2 x i8]* @real_init, i64 0, i64 0), i8* getelementptr inbounds ([2 x i8]* @.str, i64 0, i64 0)) nounwind readonly
-  ret i32 %t0
-}
-
-declare i32 @strcmp(i8*, i8*) nounwind readonly