mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-23 03:02:36 +01:00
1291b464ba
This fixes a bug at LibCallSimplifier::optimizeMemChr which does the following transformation:
```
// memchr("\r\n", C, 2) != nullptr -> (1 << C & ((1 << '\r') | (1 << '\n')))
// != 0
// after bounds check.
```
As written above, a bounds check on C (whether it is less than integer bitwidth) is done before doing `1 << C` otherwise 1 << C will overflow.
If the bounds check is false, the result of (1 << C & ...) must not be used at all, otherwise the result of shift (which is poison) will contaminate the whole results.
A correct way to encode this is `select i1 (bounds check), (1 << C & ...), false` because select does not allow the unused operand to contaminate the result.
However, this optimization was introducing `and (bounds check), (1 << C & ...)` which cannot do that.
The bug was found from compilation of this C++ code: https://reviews.llvm.org/rG2fd3037ac615#1007197
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D104901
126 lines
4.1 KiB
LLVM
126 lines
4.1 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
|
|
; Test that the strchr 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-n8:16:32"
|
|
|
|
@hello = constant [14 x i8] c"hello world\5Cn\00"
|
|
@null = constant [1 x i8] zeroinitializer
|
|
@newlines = constant [3 x i8] c"\0D\0A\00"
|
|
@chp = global i8* zeroinitializer
|
|
|
|
declare i8* @strchr(i8*, i32)
|
|
|
|
define void @test_simplify1() {
|
|
; CHECK-LABEL: @test_simplify1(
|
|
; CHECK-NEXT: store i8* getelementptr inbounds ([14 x i8], [14 x i8]* @hello, i32 0, i32 6), i8** @chp, align 4
|
|
; CHECK-NEXT: ret void
|
|
;
|
|
|
|
%str = getelementptr [14 x i8], [14 x i8]* @hello, i32 0, i32 0
|
|
%dst = call i8* @strchr(i8* %str, i32 119)
|
|
store i8* %dst, i8** @chp
|
|
ret void
|
|
}
|
|
|
|
define void @test_simplify2() {
|
|
; CHECK-LABEL: @test_simplify2(
|
|
; CHECK-NEXT: store i8* null, i8** @chp, align 4
|
|
; CHECK-NEXT: ret void
|
|
;
|
|
|
|
%str = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
|
|
%dst = call i8* @strchr(i8* %str, i32 119)
|
|
store i8* %dst, i8** @chp
|
|
ret void
|
|
}
|
|
|
|
define void @test_simplify3() {
|
|
; CHECK-LABEL: @test_simplify3(
|
|
; CHECK-NEXT: store i8* getelementptr inbounds ([14 x i8], [14 x i8]* @hello, i32 0, i32 13), i8** @chp, align 4
|
|
; CHECK-NEXT: ret void
|
|
;
|
|
|
|
%src = getelementptr [14 x i8], [14 x i8]* @hello, i32 0, i32 0
|
|
%dst = call i8* @strchr(i8* %src, i32 0)
|
|
store i8* %dst, i8** @chp
|
|
ret void
|
|
}
|
|
|
|
define void @test_simplify4(i32 %chr) {
|
|
; CHECK-LABEL: @test_simplify4(
|
|
; CHECK-NEXT: [[MEMCHR:%.*]] = call i8* @memchr(i8* noundef nonnull dereferenceable(14) getelementptr inbounds ([14 x i8], [14 x i8]* @hello, i32 0, i32 0), i32 [[CHR:%.*]], i32 14)
|
|
; CHECK-NEXT: store i8* [[MEMCHR]], i8** @chp, align 4
|
|
; CHECK-NEXT: ret void
|
|
;
|
|
|
|
%src = getelementptr [14 x i8], [14 x i8]* @hello, i32 0, i32 0
|
|
%dst = call i8* @strchr(i8* %src, i32 %chr)
|
|
store i8* %dst, i8** @chp
|
|
ret void
|
|
}
|
|
|
|
define void @test_simplify5() {
|
|
; CHECK-LABEL: @test_simplify5(
|
|
; CHECK-NEXT: store i8* getelementptr inbounds ([14 x i8], [14 x i8]* @hello, i32 0, i32 13), i8** @chp, align 4
|
|
; CHECK-NEXT: ret void
|
|
;
|
|
|
|
%src = getelementptr [14 x i8], [14 x i8]* @hello, i32 0, i32 0
|
|
%dst = call i8* @strchr(i8* %src, i32 65280)
|
|
store i8* %dst, i8** @chp
|
|
ret void
|
|
}
|
|
|
|
; Check transformation strchr(p, 0) -> p + strlen(p)
|
|
define void @test_simplify6(i8* %str) {
|
|
; CHECK-LABEL: @test_simplify6(
|
|
; CHECK-NEXT: [[STRLEN:%.*]] = call i32 @strlen(i8* noundef nonnull dereferenceable(1) [[STR:%.*]])
|
|
; CHECK-NEXT: [[STRCHR:%.*]] = getelementptr i8, i8* [[STR]], i32 [[STRLEN]]
|
|
; CHECK-NEXT: store i8* [[STRCHR]], i8** @chp, align 4
|
|
; CHECK-NEXT: ret void
|
|
;
|
|
|
|
%dst = call i8* @strchr(i8* %str, i32 0)
|
|
store i8* %dst, i8** @chp
|
|
ret void
|
|
}
|
|
|
|
; Check transformation strchr("\r\n", C) != nullptr -> (C & 9217) != 0
|
|
define i1 @test_simplify7(i32 %C) {
|
|
; CHECK-LABEL: @test_simplify7(
|
|
; CHECK-NEXT: [[TMP1:%.*]] = trunc i32 [[C:%.*]] to i16
|
|
; CHECK-NEXT: [[TMP2:%.*]] = and i16 [[TMP1]], 255
|
|
; CHECK-NEXT: [[MEMCHR_BOUNDS:%.*]] = icmp ult i16 [[TMP2]], 16
|
|
; CHECK-NEXT: [[TMP3:%.*]] = shl i16 1, [[TMP2]]
|
|
; CHECK-NEXT: [[TMP4:%.*]] = and i16 [[TMP3]], 9217
|
|
; CHECK-NEXT: [[MEMCHR_BITS:%.*]] = icmp ne i16 [[TMP4]], 0
|
|
; CHECK-NEXT: [[MEMCHR1:%.*]] = select i1 [[MEMCHR_BOUNDS]], i1 [[MEMCHR_BITS]], i1 false
|
|
; CHECK-NEXT: ret i1 [[MEMCHR1]]
|
|
;
|
|
|
|
%dst = call i8* @strchr(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @newlines, i64 0, i64 0), i32 %C)
|
|
%cmp = icmp ne i8* %dst, null
|
|
ret i1 %cmp
|
|
}
|
|
|
|
define i8* @test1(i8* %str, i32 %c) {
|
|
; CHECK-LABEL: @test1(
|
|
; CHECK-NEXT: [[RET:%.*]] = call i8* @strchr(i8* noundef nonnull dereferenceable(1) [[STR:%.*]], i32 [[C:%.*]])
|
|
; CHECK-NEXT: ret i8* [[RET]]
|
|
;
|
|
|
|
%ret = call i8* @strchr(i8* %str, i32 %c)
|
|
ret i8* %ret
|
|
}
|
|
|
|
define i8* @test2(i8* %str, i32 %c) null_pointer_is_valid {
|
|
; CHECK-LABEL: @test2(
|
|
; CHECK-NEXT: [[RET:%.*]] = call i8* @strchr(i8* noundef [[STR:%.*]], i32 [[C:%.*]])
|
|
; CHECK-NEXT: ret i8* [[RET]]
|
|
;
|
|
|
|
%ret = call i8* @strchr(i8* %str, i32 %c)
|
|
ret i8* %ret
|
|
}
|