From 407bcf8e28f417a2be94d9a0a38a0b7effcf2b94 Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Tue, 5 Jan 2021 17:43:27 +0000 Subject: [PATCH] A couple of comment tweaks Tweak a couple of comments added in the RTL-SSA series in response to reviewer feedback. gcc/ * mux-utils.h (pointer_mux::m_ptr): Tweak description of contents. * rtlanal.c (simple_regno_set): Tweak description to clarify the RMW condition. --- gcc/mux-utils.h | 8 ++++---- gcc/rtlanal.c | 8 +++++--- 2 files changed, 9 insertions(+), 7 deletions(-) diff --git a/gcc/mux-utils.h b/gcc/mux-utils.h index 169a12e..e252b56 100644 --- a/gcc/mux-utils.h +++ b/gcc/mux-utils.h @@ -139,10 +139,10 @@ public: private: pointer_mux (char *ptr) : m_ptr (ptr) {} - // The pointer value for A pointers, or the pointer value + 1 for B pointers. - // Using a pointer rather than a uintptr_t tells the compiler that second () - // can never return null, and that second_or_null () is only null if - // is_first (). + // Points to the first byte of an object for A pointers or the second + // byte of an object for B pointers. Using a pointer rather than a + // uintptr_t tells the compiler that second () can never return null, + // and that second_or_null () is only null if is_first (). char *m_ptr; }; diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c index d5b203e..d1240b0 100644 --- a/gcc/rtlanal.c +++ b/gcc/rtlanal.c @@ -1458,11 +1458,13 @@ set_of (const_rtx pat, const_rtx insn) /* Check whether instruction pattern PAT contains a SET with the following properties: - - the SET is executed unconditionally; - - the destination of the SET is write-only rather than read-write; and + - the SET is executed unconditionally; and - either: - the destination of the SET is a REG that contains REGNO; or - - the destination of the SET is a SUBREG of such a REG. + - both: + - the destination of the SET is a SUBREG of such a REG; and + - writing to the subreg clobbers all of the SUBREG_REG + (in other words, read_modify_subreg_p is false). If PAT does have a SET like that, return the set, otherwise return null. -- 2.7.4