Commit Graph

7 Commits

Author SHA1 Message Date
Qiu Chaofan 5c18d11366 [SPE] Disable strict-fp for SPE by default
As discussed in PR50385, strict-fp on PowerPC SPE has not been handled
well. This patch disables it by default for SPE.

Reviewed By: nemanjai, vit9696, jhibbits

Differential Revision: https://reviews.llvm.org/D103235
2021-05-28 00:14:35 +08:00
Qiu Chaofan 8ecc8520bc [FPEnv] [Clang] Enable constrained FP support for PowerPC
d4ce862f introduced HasStrictFP to disable generating constrained FP
operations for platforms lacking support. Since work for enabling
constrained FP on PowerPC is almost done, we'd like to enable it.

Reviewed By: kpn, steven.zhang

Differential Revision: https://reviews.llvm.org/D87223
2020-09-12 00:39:52 +08:00
Qiu Chaofan 88ff4d2ca1 [PowerPC] Fix STRICT_FRINT/STRICT_FNEARBYINT lowering
In standard C library, both rint and nearbyint returns rounding result
in current rounding mode. But nearbyint never raises inexact exception.
On PowerPC, x(v|s)r(d|s)pic may modify FPSCR XX, raising inexact
exception. So we can't select constrained fnearbyint into xvrdpic.

One exception here is xsrqpi, which will not raise inexact exception, so
fnearbyint f128 is okay here.

Reviewed By: uweigand

Differential Revision: https://reviews.llvm.org/D87220
2020-09-09 22:40:58 +08:00
Kevin P. Neal d4ce862f2a Reland "[FPEnv][Clang][Driver] Disable constrained floating point on targets lacking support."
We currently have strict floating point/constrained floating point enabled
for all targets. Constrained SDAG nodes get converted to the regular ones
before reaching the target layer. In theory this should be fine.

However, the changes are exposed to users through multiple clang options
already in use in the field, and the changes are _completely_ _untested_
on almost all of our targets. Bugs have already been found, like
"https://bugs.llvm.org/show_bug.cgi?id=45274".

This patch disables constrained floating point options in clang everywhere
except X86 and SystemZ. A warning will be printed when this happens.

Use the new -fexperimental-strict-floating-point flag to force allowing
strict floating point on hosts that aren't already marked as supporting
it (X86 and SystemZ).

Differential Revision: https://reviews.llvm.org/D80952
2020-07-10 08:49:45 -04:00
Kevin P. Neal 916e2ca997 Revert "[FPEnv][Clang][Driver] Disable constrained floating point on targets lacking support."
My mistake, I had a blocking reviewer.

This reverts commit 39d2ae0afb.
This reverts commit bfdafa32a0.
This reverts commit 2b35511350.

Differential Revision: https://reviews.llvm.org/D80952
2020-07-06 14:57:45 -04:00
Kevin P. Neal 39d2ae0afb [FPEnv][Clang][Driver] Disable constrained floating point on targets lacking support.
We currently have strict floating point/constrained floating point enabled
for all targets. Constrained SDAG nodes get converted to the regular ones
before reaching the target layer. In theory this should be fine.

However, the changes are exposed to users through multiple clang options
already in use in the field, and the changes are _completely_ _untested_
on almost all of our targets. Bugs have already been found, like
"https://bugs.llvm.org/show_bug.cgi?id=45274".

This patch disables constrained floating point options in clang everywhere
except X86 and SystemZ. A warning will be printed when this happens.

Differential Revision: https://reviews.llvm.org/D80952
2020-07-06 13:32:49 -04:00
Andrew Wock 15edd7aaa7 [FPEnv] PowerPC-specific builtin constrained FP enablement
This change enables PowerPC compiler builtins to generate constrained
floating point operations when clang is indicated to do so.

A couple of possibly unexpected backend divergences between constrained
floating point and regular behavior are highlighted under the test tag
FIXME-CHECK. This may be something for those on the PPC backend to look
at.

Patch by: Drew Wock <drew.wock@sas.com>

Differential Revision: https://reviews.llvm.org/D82020
2020-06-25 11:42:58 -04:00