llvm-project

Commit Graph

Author	SHA1	Message	Date
Sanjay Patel	74c7fb002f	[CodeGen] use nsw negation for builtin abs The clang builtins have the same semantics as the stdlib functions. The stdlib functions are defined in section 7.20.6.1 of the C standard with: "If the result cannot be represented, the behavior is undefined." That lets us mark the negation with 'nsw' because "sub i32 0, INT_MIN" would be UB/poison. Differential Revision: https://reviews.llvm.org/D47202 llvm-svn: 333038	2018-05-22 23:02:13 +00:00
Sanjay Patel	1ff6b27940	[CodeGen] produce the LLVM canonical form of abs We chose the 'slt' form as canonical in IR with: rL332819 ...so we should generate that form directly for efficiency. llvm-svn: 332989	2018-05-22 15:36:50 +00:00
Sanjay Patel	b6e5d4ead1	[CodeGen] add tests for abs builtins; NFC llvm-svn: 332988	2018-05-22 15:11:59 +00:00

Author

SHA1

Message

Date

Sanjay Patel

74c7fb002f

[CodeGen] use nsw negation for builtin abs

The clang builtins have the same semantics as the stdlib functions.
The stdlib functions are defined in section 7.20.6.1 of the C standard with:
"If the result cannot be represented, the behavior is undefined."

That lets us mark the negation with 'nsw' because "sub i32 0, INT_MIN" would
be UB/poison.

Differential Revision: https://reviews.llvm.org/D47202

llvm-svn: 333038

2018-05-22 23:02:13 +00:00

Sanjay Patel

1ff6b27940

[CodeGen] produce the LLVM canonical form of abs

We chose the 'slt' form as canonical in IR with:
rL332819
...so we should generate that form directly for efficiency.

llvm-svn: 332989

2018-05-22 15:36:50 +00:00

Sanjay Patel

b6e5d4ead1

[CodeGen] add tests for abs builtins; NFC

llvm-svn: 332988

2018-05-22 15:11:59 +00:00

3 Commits