From 881083d629878da043d3f0d7ab5584e77253626c Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Thu, 4 Dec 2014 14:44:57 +0000 Subject: [PATCH] match-and-simplify.texi: Update for recent changes. 2014-12-04 Richard Biener * doc/match-and-simplify.texi: Update for recent changes. From-SVN: r218372 --- gcc/ChangeLog | 4 ++++ gcc/doc/match-and-simplify.texi | 40 +++++++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 7902ac01ed6..f937c44f30d 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +2014-12-04 Richard Biener + + * doc/match-and-simplify.texi: Update for recent changes. + 2014-12-04 Martin Jambor * ipa-prop.h (ipa_alignment): New type. diff --git a/gcc/doc/match-and-simplify.texi b/gcc/doc/match-and-simplify.texi index d63d8b81ead..2d8faf881fc 100644 --- a/gcc/doc/match-and-simplify.texi +++ b/gcc/doc/match-and-simplify.texi @@ -224,6 +224,46 @@ In this example the pattern will be repeated four times with @code{plus, minus, minus}, @code{minus, plus, plus}, @code{minus, plus, minus}. +To avoid repeating operator lists in @code{for} you can name +them via + +@smallexample +(define_operator_list pmm plus minus mult) +@end smallexample + +and use them in @code{for} operator lists where they get expanded. + +@smallexample +(for opa (pmm trunc_div) + (simplify... +@end smallexample + +So this example iterates over @code{plus}, @code{minus}, @code{mult} +and @code{trunc_div}. + +Using operator lists can also remove the need to explicitely write +a @code{for}. All operator list uses that appear in a @code{simplify} +or @code{match} pattern in operator positions will implicitely +be added to a new @code{for}. For example + +@smallexample +(define_operator_list SQRT BUILT_IN_SQRTF BUILT_IN_SQRT BUILT_IN_SQRTL) +(define_operator_list POW BUILT_IN_POWF BUILT_IN_POW BUILT_IN_POWL) +(simplify + (SQRT (POW @@0 @@1)) + (POW (abs @@0) (mult @@1 @{ built_real (TREE_TYPE (@@1), dconsthalf); @}))) +@end smallexample + +is the same as + +@smallexample +(for SQRT (BUILT_IN_SQRTF BUILT_IN_SQRT BUILT_IN_SQRTL) + POW (BUILT_IN_POWF BUILT_IN_POW BUILT_IN_POWL) + (simplify + (SQRT (POW @@0 @@1)) + (POW (abs @@0) (mult @@1 @{ built_real (TREE_TYPE (@@1), dconsthalf); @})))) +@end smallexample + Another building block are @code{with} expressions in the result expression which nest the generated code in a new C block followed by its argument: -- 2.30.2