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Matthias Braun be57ef6b4f SimplifyLibCalls: Optimize wcslen
Refactor the strlen optimization code to work for both strlen and wcslen.

This especially helps with programs in the wild where people pass
L"string"s to const std::wstring& function parameters and the wstring
constructor gets inlined.

This also fixes a lingerind API problem/bug in getConstantStringInfo()
where zeroinitializers would always give you an empty string (without a
length) back regardless of the actual length of the initializer which
did not work well in the TrimAtNul==false causing the PR mentioned
below.

Note that the fixed getConstantStringInfo() needed fixes to SelectionDAG
memcpy lowering and may lead to some cases for out-of-bounds
zeroinitializer accesses not getting optimized anymore. So some code
with UB may produce out of bound memory reads now instead of just
producing zeros.

The refactoring "accidentally" fixes http://llvm.org/PR32124

Differential Revision: https://reviews.llvm.org/D32839

llvm-svn: 303461
2017-05-19 22:37:09 +00:00

19 lines
576 B
LLVM

; Test that the wcslen library call simplifier works correctly.
;
; RUN: opt < %s -instcombine -S | FileCheck %s
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
@hello = constant [6 x i32] [i32 104, i32 101, i32 108, i32 108, i32 111, i32 0]
declare i64 @wcslen(i32*, i32)
define i64 @test_no_simplify1() {
; CHECK-LABEL: @test_no_simplify1(
%hello_p = getelementptr [6 x i32], [6 x i32]* @hello, i64 0, i64 0
%hello_l = call i64 @wcslen(i32* %hello_p, i32 187)
; CHECK-NEXT: %hello_l = call i64 @wcslen
ret i64 %hello_l
; CHECK-NEXT: ret i64 %hello_l
}