| Message ID | 2ee6aa6b-52aa-411b-1611-f68da3836044@oracle.com |
|---|---|
| State | New |
| Headers | show |
| Series | Minor documentation correction in aarch64-simd.md | expand |
On Wed, Apr 25, 2018 at 03:17:28PM -0500, Indu Bhagat wrote: > In function minmax_replacement in tree-ssa-phiopt.c, MIN_EXPR/MAX_EXPR > are substituted for when the following condition is false - (HONOR_NANS > (type) || HONOR_SIGNED_ZEROS (type)). So for FP mode, this is false when > _both_ of the following conditions are fulfilled : 1. flag_signed_zeros > is zero and 2. flag_finite_math_only is set. So, the documentation in > aarch64-simd.md is partially misleading. Here is a patch to correct > that. Thanks This is OK for trunk. Thanks, James > gcc/ChangeLog: > > * config/aarch64/aarch64-simd.md: correct flags text for > MIN_EXPR replacement > diff --git a/gcc/config/aarch64/aarch64-simd.md b/gcc/config/aarch64/aarch64-simd.md > index 1154fc3..7fd20fd 100644 > --- a/gcc/config/aarch64/aarch64-simd.md > +++ b/gcc/config/aarch64/aarch64-simd.md > @@ -2211,8 +2211,9 @@ > ;; Max/Min are introduced by idiom recognition by GCC's mid-end. An > ;; expression like: > ;; a = (b < c) ? b : c; > -;; is idiom-matched as MIN_EXPR<b,c> only if -ffinite-math-only is enabled > -;; either explicitly or indirectly via -ffast-math. > +;; is idiom-matched as MIN_EXPR<b,c> only if -ffinite-math-only and > +;; -fno-signed-zeros are enabled either explicitly or indirectly via > +;; -ffast-math. > ;; > ;; MIN_EXPR and MAX_EXPR eventually map to 'smin' and 'smax' in RTL. > ;; The 'smax' and 'smin' RTL standard pattern names do not specify which
diff --git a/gcc/config/aarch64/aarch64-simd.md b/gcc/config/aarch64/aarch64-simd.md index 1154fc3..7fd20fd 100644 --- a/gcc/config/aarch64/aarch64-simd.md +++ b/gcc/config/aarch64/aarch64-simd.md @@ -2211,8 +2211,9 @@ ;; Max/Min are introduced by idiom recognition by GCC's mid-end. An ;; expression like: ;; a = (b < c) ? b : c; -;; is idiom-matched as MIN_EXPR<b,c> only if -ffinite-math-only is enabled -;; either explicitly or indirectly via -ffast-math. +;; is idiom-matched as MIN_EXPR<b,c> only if -ffinite-math-only and +;; -fno-signed-zeros are enabled either explicitly or indirectly via +;; -ffast-math. ;; ;; MIN_EXPR and MAX_EXPR eventually map to 'smin' and 'smax' in RTL. ;; The 'smax' and 'smin' RTL standard pattern names do not specify which
In function minmax_replacement in tree-ssa-phiopt.c, MIN_EXPR/MAX_EXPR are substituted for when the following condition is false - (HONOR_NANS (type) || HONOR_SIGNED_ZEROS (type)). So for FP mode, this is false when _both_ of the following conditions are fulfilled : 1. flag_signed_zeros is zero and 2. flag_finite_math_only is set. So, the documentation in aarch64-simd.md is partially misleading. Here is a patch to correct that. Thanks ----------------------- gcc/ChangeLog: * config/aarch64/aarch64-simd.md: correct flags text for MIN_EXPR replacement