instcombine: Migrate strspn optimizations

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167568 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 56 insertions, 16 deletions

diff --git a/test/Transforms/InstCombine/strspn-1.ll b/test/Transforms/InstCombine/strspn-1.ll
new file mode 100644
index 0000000000..393f88735b
--- /dev/null
+++ b/test/Transforms/InstCombine/strspn-1.ll
@@ -0,0 +1,56 @@
+; Test that the strspn 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"
+
+@abcba = constant [6 x i8] c"abcba\00"
+@abc = constant [4 x i8] c"abc\00"
+@null = constant [1 x i8] zeroinitializer
+
+declare i64 @strspn(i8*, i8*)
+
+; Check strspn(s, "") -> 0.
+
+define i64 @test_simplify1(i8* %str) {
+; CHECK: @test_simplify1
+  %pat = getelementptr [1 x i8]* @null, i32 0, i32 0
+
+  %ret = call i64 @strspn(i8* %str, i8* %pat)
+  ret i64 %ret
+; CHECK-NEXT: ret i64 0
+}
+
+; Check strspn("", s) -> 0.
+
+define i64 @test_simplify2(i8* %pat) {
+; CHECK: @test_simplify2
+  %str = getelementptr [1 x i8]* @null, i32 0, i32 0
+
+  %ret = call i64 @strspn(i8* %str, i8* %pat)
+  ret i64 %ret
+; CHECK-NEXT: ret i64 0
+}
+
+; Check strspn(s1, s2), where s1 and s2 are constants.
+
+define i64 @test_simplify3() {
+; CHECK: @test_simplify3
+  %str = getelementptr [6 x i8]* @abcba, i32 0, i32 0
+  %pat = getelementptr [4 x i8]* @abc, i32 0, i32 0
+
+  %ret = call i64 @strspn(i8* %str, i8* %pat)
+  ret i64 %ret
+; CHECK-NEXT: ret i64 5
+}
+
+; Check cases that shouldn't be simplified.
+
+define i64 @test_no_simplify1(i8* %str, i8* %pat) {
+; CHECK: @test_no_simplify1
+
+  %ret = call i64 @strspn(i8* %str, i8* %pat)
+; CHECK-NEXT: %ret = call i64 @strspn(i8* %str, i8* %pat)
+  ret i64 %ret
+; CHECK-NEXT: ret i64 %ret
+}
diff --git a/test/Transforms/SimplifyLibCalls/StrSpn.ll b/test/Transforms/SimplifyLibCalls/StrSpn.ll
index 800c190883..2660ee9800 100644
--- a/test/Transforms/SimplifyLibCalls/StrSpn.ll
+++ b/test/Transforms/SimplifyLibCalls/StrSpn.ll
@@ -6,22 +6,6 @@ target datalayout = "-p:64:64:64"
 @abc = constant [4 x i8] c"abc\00"
 @null = constant [1 x i8] zeroinitializer
 
-declare i64 @strspn(i8*, i8*)
-
-define i64 @testspn(i8* %s1, i8* %s2) {
-  	%abcba_p = getelementptr [6 x i8]* @abcba, i32 0, i32 0
-	%abc_p = getelementptr [4 x i8]* @abc, i32 0, i32 0
-	%null_p = getelementptr [1 x i8]* @null, i32 0, i32 0
-	%test1 = call i64 @strspn(i8* %s1, i8* %null_p)
-	%test2 = call i64 @strspn(i8* %null_p, i8* %s2)
-	%test3 = call i64 @strspn(i8* %abcba_p, i8* %abc_p)
-; CHECK-NOT: call i64 @strspn
-	%test4 = call i64 @strspn(i8* %s1, i8* %s2)
-; CHECK: call i64 @strspn(i8* %s1, i8* %s2)
-	ret i64 %test3
-; CHECK: ret i64 5
-}
-
 declare i64 @strcspn(i8*, i8*)
 
 define i64 @testcspn(i8* %s1, i8* %s2) {