instcombine: Migrate strcspn optimizations

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167675 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 87 insertions, 25 deletions

diff --git a/test/Transforms/InstCombine/disable-simplify-libcalls.ll b/test/Transforms/InstCombine/disable-simplify-libcalls.ll
index 155c97c010..d81e9ae5bd 100644
--- a/test/Transforms/InstCombine/disable-simplify-libcalls.ll
+++ b/test/Transforms/InstCombine/disable-simplify-libcalls.ll
@@ -36,6 +36,7 @@ declare i64 @strtol(i8*, i8**, i32)
 declare i64 @strtoll(i8*, i8**, i32)
 declare i64 @strtoul(i8*, i8**, i32)
 declare i64 @strtoull(i8*, i8**, i32)
+declare i64 @strcspn(i8*, i8*)
 
 define double @t1(double %x) {
 ; CHECK: @t1
@@ -225,3 +226,11 @@ define i64 @t24(i8** %y) {
   ret i64 %ret
 ; CHECK: call i64 @strtoull
 }
+
+define i64 @t25(i8* %y) {
+; CHECK: @t25
+  %x = getelementptr [1 x i8]* @empty, i32 0, i32 0
+  %ret = call i64 @strcspn(i8* %x, i8* %y)
+  ret i64 %ret
+; CHECK: call i64 @strcspn
+}
diff --git a/test/Transforms/InstCombine/strcspn-1.ll b/test/Transforms/InstCombine/strcspn-1.ll
new file mode 100644
index 0000000000..60fad897b2
--- /dev/null
+++ b/test/Transforms/InstCombine/strcspn-1.ll
@@ -0,0 +1,57 @@
+; Test that the strcspn library call simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+
+@abcba = constant [6 x i8] c"abcba\00"
+@abc = constant [4 x i8] c"abc\00"
+@null = constant [1 x i8] zeroinitializer
+
+declare i64 @strcspn(i8*, i8*)
+
+; Check strcspn(s, "") -> strlen(s).
+
+define i64 @test_simplify1(i8* %str) {
+; CHECK: @test_simplify1
+  %pat = getelementptr [1 x i8]* @null, i32 0, i32 0
+
+  %ret = call i64 @strcspn(i8* %str, i8* %pat)
+; CHECK-NEXT: [[VAR:%[a-z]+]] = call i64 @strlen(i8* %str)
+  ret i64 %ret
+; CHECK-NEXT: ret i64 [[VAR]]
+}
+
+; Check strcspn("", s) -> 0.
+
+define i64 @test_simplify2(i8* %pat) {
+; CHECK: @test_simplify2
+  %str = getelementptr [1 x i8]* @null, i32 0, i32 0
+
+  %ret = call i64 @strcspn(i8* %str, i8* %pat)
+  ret i64 %ret
+; CHECK-NEXT: ret i64 0
+}
+
+; Check strcspn(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 @strcspn(i8* %str, i8* %pat)
+  ret i64 %ret
+; CHECK-NEXT: ret i64 0
+}
+
+; Check cases that shouldn't be simplified.
+
+define i64 @test_no_simplify1(i8* %str, i8* %pat) {
+; CHECK: @test_no_simplify1
+
+  %ret = call i64 @strcspn(i8* %str, i8* %pat)
+; CHECK-NEXT: %ret = call i64 @strcspn(i8* %str, i8* %pat)
+  ret i64 %ret
+; CHECK-NEXT: ret i64 %ret
+}
diff --git a/test/Transforms/InstCombine/strcspn-2.ll b/test/Transforms/InstCombine/strcspn-2.ll
new file mode 100644
index 0000000000..4e2393686c
--- /dev/null
+++ b/test/Transforms/InstCombine/strcspn-2.ll
@@ -0,0 +1,21 @@
+; Test that the strcspn library call simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+
+@null = constant [1 x i8] zeroinitializer
+
+declare double @strcspn(i8*, i8*)
+
+; Check that strcspn functions with the wrong prototype aren't simplified.
+
+define double @test_no_simplify1(i8* %pat) {
+; CHECK: @test_no_simplify1
+  %str = getelementptr [1 x i8]* @null, i32 0, i32 0
+
+  %ret = call double @strcspn(i8* %str, i8* %pat)
+; CHECK-NEXT: call double @strcspn
+  ret double %ret
+; CHECK-NEXT: ret double %ret
+}
diff --git a/test/Transforms/SimplifyLibCalls/StrSpn.ll b/test/Transforms/SimplifyLibCalls/StrSpn.ll
deleted file mode 100644
index 2660ee9800..0000000000
--- a/test/Transforms/SimplifyLibCalls/StrSpn.ll
+++ /dev/null
@@ -1,25 +0,0 @@
-; RUN: opt < %s -simplify-libcalls -S | FileCheck %s
-
-target datalayout = "-p:64:64:64"
-
-@abcba = constant [6 x i8] c"abcba\00"
-@abc = constant [4 x i8] c"abc\00"
-@null = constant [1 x i8] zeroinitializer
-
-declare i64 @strcspn(i8*, i8*)
-
-define i64 @testcspn(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 @strcspn(i8* %s1, i8* %null_p)
-; CHECK: call i64 @strlen(i8* %s1)
-	%test2 = call i64 @strcspn(i8* %null_p, i8* %s2)
-	%test3 = call i64 @strcspn(i8* %abcba_p, i8* %abc_p)
-; CHECK-NOT: call i64 @strcspn
-	%test4 = call i64 @strcspn(i8* %s1, i8* %s2)
-; CHECK: call i64 @strcspn(i8* %s1, i8* %s2)
-        %add0 = add i64 %test1, %test3
-; CHECK: add i64 %{{.+}}, 0
-	ret i64 %add0
-}