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C Backend generates negation of negative integers as predecrement #968

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llvmbot opened this issue Jul 14, 2005 · 1 comment
Closed

C Backend generates negation of negative integers as predecrement #968

llvmbot opened this issue Jul 14, 2005 · 1 comment
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bugzilla Issues migrated from bugzilla compile-fail Use [accepts-invalid] and [rejects-valid] instead

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@llvmbot
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llvmbot commented Jul 14, 2005

Bugzilla Link 596
Resolution FIXED
Resolved on Feb 22, 2010 12:49
Version 1.0
OS All
Attachments Testcase to reproduce the problem
Reporter LLVM Bugzilla Contributor

Extended Description

The C Backend takes the (soon to be) attached test case and miscompiles it into
invalid C code.

Specifically, in the case where a negative integer is negated, the C Backend
generates a minus for the negation and then another minus for the integer. This
"minus minus" becomes the C pre-decrement operator, which is incorrect.

i.e. we generate --65535 instead of -(-65535).
@llvmbot
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llvmbot commented Jul 15, 2005

Fixed.

Patch here:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20050711/027083.html

Regression test here:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20050711/027084.html

@llvmbot llvmbot transferred this issue from llvm/llvm-bugzilla-archive Dec 3, 2021
kitano-metro pushed a commit to RIKEN-RCCS/llvm-project that referenced this issue Feb 14, 2023
refs llvm#968 TSVC s1111~s115の資源情報定義
02d771d
kitano-metro pushed a commit to RIKEN-RCCS/llvm-project that referenced this issue Feb 14, 2023
refs llvm#968 Immがない場合の考慮を追加
186f6b0
kitano-metro pushed a commit to RIKEN-RCCS/llvm-project that referenced this issue Feb 14, 2023
refs llvm#968 レビュー指摘反映
a4e24ad
This was referenced Jun 6, 2024
Closed
Open
keryell pushed a commit to keryell/llvm-project that referenced this issue Oct 19, 2024
@ghehg @lanza
[CIR][CIRGen][NFC] Consolidate RUN lines for builtin tests (llvm#968)
ffd2935 
There is no change to testing functionality. This refacot let those
files have the same Run options that is easier to maintain and extend.
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