Matt Arsenault f48425edca
AMDGPU: Match fract pattern with swapped edge case check (#189081)
A fract implementation can equivalently be written as
  r = fmin(x - floor(x))
  r = isnan(x) ? x : r;
  r = isinf(x) ? 0.0 : r;

or:
  r = fmin(x - floor(x));
  r = isinf(x) ? 0.0 : r;
  r = isnan(x) ? x : r;

Previously this only matched the previous form. Match
the case where the isinf check is the inner clamp. There are
a few more ways to write this pattern (e.g., move the clamp of
infinity to the input) but I haven't encountered that in the wild.

The existing code seems to be trying too hard to match noncanonical
variants of the pattern. Only handles the result that all 4 permutations
of compare and select produce out of instcombine.
2026-03-31 09:13:58 +02:00
..
2025-12-05 12:39:50 +00:00
2025-12-05 12:39:50 +00:00
2025-12-05 12:39:50 +00:00

+==============================================================================+
| How to organize the lit tests                                                |
+==============================================================================+

- If you write a test for matching a single DAG opcode or intrinsic, it should
  go in a file called {opcode_name,intrinsic_name}.ll (e.g. fadd.ll)

- If you write a test that matches several DAG opcodes and checks for a single
  ISA instruction, then that test should go in a file called {ISA_name}.ll (e.g.
  bfi_int.ll

- For all other tests, use your best judgement for organizing tests and naming
  the files.

+==============================================================================+
| Naming conventions                                                           |
+==============================================================================+

- Use dash '-' and not underscore '_' to separate words in file names, unless
  the file is named after a DAG opcode or ISA instruction that has an
  underscore '_' in its name.