forked from OSchip/llvm-project
de47590589
`LCSSASafePhiForRAUW` as computed was incorrect -- in cases like
these (this exact example does not actually trigger the bug):
define i32 @f(i32 %n, i1* %c) {
entry:
br label %outer.loop
outer.loop:
br label %inner.loop
inner.loop:
%iv = phi i32 [ 0, %outer.loop ], [ %iv.inc, %inner.loop ]
%iv.inc = add nuw nsw i32 %iv, 1
%tc = udiv i32 %n, 13
%be.cond = icmp ult i32 %iv, %tc
br i1 %be.cond, label %inner.loop, label %inner.exit
inner.exit:
%iv.lcssa = phi i32 [ %iv, %inner.loop ]
%outer.be.cond = load volatile i1, i1* %c
br i1 %outer.be.cond, label %outer.loop, label %leave
leave:
%iv.lcssa.lcssa = phi i32 [ %iv.lcssa, %inner.exit ]
ret i32 %iv.lcssa.lcssa
}
`LCSSASafePhiForRAUW` is true for `%iv.lcssa` when re-rewriting the exit
value of `%iv` for `%inner.loop` to `%tc` (this can happen due to
`SCEVExpander::findExistingExpansion`), but the RAUW breaks LCSSA.
To fix this, instead of computing `SafePhi` with special logic, decide
the safety of RAUW directly via `replacementPreservesLCSSAForm`.
llvm-svn: 258016
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| .. | ||
| autoconf | ||
| bindings | ||
| cmake | ||
| docs | ||
| examples | ||
| include | ||
| lib | ||
| projects | ||
| resources | ||
| test | ||
| tools | ||
| unittests | ||
| utils | ||
| .arcconfig | ||
| .clang-format | ||
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| .gitignore | ||
| CMakeLists.txt | ||
| CODE_OWNERS.TXT | ||
| CREDITS.TXT | ||
| LICENSE.TXT | ||
| LLVMBuild.txt | ||
| Makefile | ||
| Makefile.common | ||
| Makefile.config.in | ||
| Makefile.rules | ||
| README.txt | ||
| configure | ||
| llvm.spec.in | ||
README.txt
Low Level Virtual Machine (LLVM) ================================ This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. Please see the documentation provided in docs/ for further assistance with LLVM, and in particular docs/GettingStarted.rst for getting started with LLVM and docs/README.txt for an overview of LLVM's documentation setup. If you are writing a package for LLVM, see docs/Packaging.rst for our suggestions.