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llvm-mirror/test/Transforms/InstCombine/strlen-1.ll
David L Kreitzer cc655b3f3d Simplify strlen to a subtraction for certain cases.
Patch by Li Huang (li1.huang@intel.com)

Differential Revision: http://reviews.llvm.org/D18230

llvm-svn: 266200
2016-04-13 14:31:06 +00:00

178 lines
5.3 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; Test that the strlen 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"
@longer = constant [7 x i8] c"longer\00"
@null = constant [1 x i8] zeroinitializer
@null_hello = constant [7 x i8] c"\00hello\00"
@nullstring = constant i8 0
@a = common global [32 x i8] zeroinitializer, align 1
@null_hello_mid = constant [13 x i8] c"hello wor\00ld\00"
declare i32 @strlen(i8*)
; Check strlen(string constant) -> integer constant.
define i32 @test_simplify1() {
; CHECK-LABEL: @test_simplify1(
; CHECK-NEXT: ret i32 5
;
%hello_p = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
%hello_l = call i32 @strlen(i8* %hello_p)
ret i32 %hello_l
}
define i32 @test_simplify2() {
; CHECK-LABEL: @test_simplify2(
; CHECK-NEXT: ret i32 0
;
%null_p = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
%null_l = call i32 @strlen(i8* %null_p)
ret i32 %null_l
}
define i32 @test_simplify3() {
; CHECK-LABEL: @test_simplify3(
; CHECK-NEXT: ret i32 0
;
%null_hello_p = getelementptr [7 x i8], [7 x i8]* @null_hello, i32 0, i32 0
%null_hello_l = call i32 @strlen(i8* %null_hello_p)
ret i32 %null_hello_l
}
define i32 @test_simplify4() {
; CHECK-LABEL: @test_simplify4(
; CHECK-NEXT: ret i32 0
;
%len = tail call i32 @strlen(i8* @nullstring) nounwind
ret i32 %len
}
; Check strlen(x) == 0 --> *x == 0.
define i1 @test_simplify5() {
; CHECK-LABEL: @test_simplify5(
; CHECK-NEXT: ret i1 false
;
%hello_p = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
%hello_l = call i32 @strlen(i8* %hello_p)
%eq_hello = icmp eq i32 %hello_l, 0
ret i1 %eq_hello
}
define i1 @test_simplify6() {
; CHECK-LABEL: @test_simplify6(
; CHECK-NEXT: ret i1 true
;
%null_p = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
%null_l = call i32 @strlen(i8* %null_p)
%eq_null = icmp eq i32 %null_l, 0
ret i1 %eq_null
}
; Check strlen(x) != 0 --> *x != 0.
define i1 @test_simplify7() {
; CHECK-LABEL: @test_simplify7(
; CHECK-NEXT: ret i1 true
;
%hello_p = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
%hello_l = call i32 @strlen(i8* %hello_p)
%ne_hello = icmp ne i32 %hello_l, 0
ret i1 %ne_hello
}
define i1 @test_simplify8() {
; CHECK-LABEL: @test_simplify8(
; CHECK-NEXT: ret i1 false
;
%null_p = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
%null_l = call i32 @strlen(i8* %null_p)
%ne_null = icmp ne i32 %null_l, 0
ret i1 %ne_null
}
define i32 @test_simplify9(i1 %x) {
; CHECK-LABEL: @test_simplify9(
; CHECK-NEXT: [[TMP1:%.*]] = select i1 %x, i32 5, i32 6
; CHECK-NEXT: ret i32 [[TMP1]]
;
%hello = getelementptr [6 x i8], [6 x i8]* @hello, i32 0, i32 0
%longer = getelementptr [7 x i8], [7 x i8]* @longer, i32 0, i32 0
%s = select i1 %x, i8* %hello, i8* %longer
%l = call i32 @strlen(i8* %s)
ret i32 %l
}
; Check the case that should be simplified to a sub instruction.
; strlen(@hello + x) --> 5 - x
define i32 @test_simplify10(i32 %x) {
; CHECK-LABEL: @test_simplify10(
; CHECK-NEXT: [[TMP1:%.*]] = sub i32 5, %x
; CHECK-NEXT: ret i32 [[TMP1]]
;
%hello_p = getelementptr inbounds [6 x i8], [6 x i8]* @hello, i32 0, i32 %x
%hello_l = call i32 @strlen(i8* %hello_p)
ret i32 %hello_l
}
; strlen(@null_hello_mid + (x & 7)) --> 9 - (x & 7)
define i32 @test_simplify11(i32 %x) {
; CHECK-LABEL: @test_simplify11(
; CHECK-NEXT: [[AND:%.*]] = and i32 %x, 7
; CHECK-NEXT: [[TMP1:%.*]] = sub nsw i32 9, [[AND]]
; CHECK-NEXT: ret i32 [[TMP1]]
;
%and = and i32 %x, 7
%hello_p = getelementptr inbounds [13 x i8], [13 x i8]* @null_hello_mid, i32 0, i32 %and
%hello_l = call i32 @strlen(i8* %hello_p)
ret i32 %hello_l
}
; Check cases that shouldn't be simplified.
define i32 @test_no_simplify1() {
; CHECK-LABEL: @test_no_simplify1(
; CHECK-NEXT: [[A_L:%.*]] = call i32 @strlen(i8* getelementptr inbounds ([32 x i8], [32 x i8]* @a, i32 0, i32 0))
; CHECK-NEXT: ret i32 [[A_L]]
;
%a_p = getelementptr [32 x i8], [32 x i8]* @a, i32 0, i32 0
%a_l = call i32 @strlen(i8* %a_p)
ret i32 %a_l
}
; strlen(@null_hello + x) should not be simplified to a sub instruction.
define i32 @test_no_simplify2(i32 %x) {
; CHECK-LABEL: @test_no_simplify2(
; CHECK-NEXT: [[HELLO_P:%.*]] = getelementptr inbounds [7 x i8], [7 x i8]* @null_hello, i32 0, i32 %x
; CHECK-NEXT: [[HELLO_L:%.*]] = call i32 @strlen(i8* [[HELLO_P]])
; CHECK-NEXT: ret i32 [[HELLO_L]]
;
%hello_p = getelementptr inbounds [7 x i8], [7 x i8]* @null_hello, i32 0, i32 %x
%hello_l = call i32 @strlen(i8* %hello_p)
ret i32 %hello_l
}
; strlen(@null_hello_mid + (x & 15)) should not be simplified to a sub instruction.
define i32 @test_no_simplify3(i32 %x) {
; CHECK-LABEL: @test_no_simplify3(
; CHECK-NEXT: [[AND:%.*]] = and i32 %x, 15
; CHECK-NEXT: [[HELLO_P:%.*]] = getelementptr inbounds [13 x i8], [13 x i8]* @null_hello_mid, i32 0, i32 [[AND]]
; CHECK-NEXT: [[HELLO_L:%.*]] = call i32 @strlen(i8* [[HELLO_P]])
; CHECK-NEXT: ret i32 [[HELLO_L]]
;
%and = and i32 %x, 15
%hello_p = getelementptr inbounds [13 x i8], [13 x i8]* @null_hello_mid, i32 0, i32 %and
%hello_l = call i32 @strlen(i8* %hello_p)
ret i32 %hello_l
}