FW: [PATCH,ARM][1/6] Merge LDR/STR into LDRD/STRD with -O2 in Thumb

[Greta Yorsh]

Here is the correct file 1-ldrdstrd.patch.  Sorry.

-- Greta

> -----Original Message-----
> From: Greta Yorsh [mailto:Greta.Yorsh@arm.com]
> Sent: 07 November 2011 11:45
> To: gcc-patches@gcc.gnu.org
> Cc: nickc@redhat.com; Richard Earnshaw; paul@codesourcery.com; Ramana
> Radhakrishnan; Carrot@google.com
> Subject: [PATCH,ARM][1/6] Merge LDR/STR into LDRD/STRD with -O2 in
> Thumb
> 
> Generate LDRD/STRD in Thumb mode with -O2 for CPUs that set
> "prefer_ldrd_strd" tune flag. This flag is currently set only for
> cortex-a15.
> 
> The patch consists of
> * define_insn for LDRD/STRD,
> * peephole2 patterns that merge LDR/STR into LDRD/STRD,
> * peephole2 patterns that attempt to rename and reorder registers to
> enable
> LDRD/STRD, and
> * fix existing tests to accept LDRD/STRD in addition to LDM/STM.
> 
> The new patterns and peephole optimizations are placed in a new file,
> ldrdstrd0.md, which is included in arm.md before ldmstm.md, and thus
> when
> LDRD/STRD cannot be generated, LDM/STM may still be generated. The file
> ldrdstrd0.md is automatically generated (see patch no. 3 in the
> series).
> 
> This patch depends on the patch for prefer_ldrd_strd tune flag,
> submitted
> here:
> http://gcc.gnu.org/ml/gcc-patches/2011-10/msg00858.html
> 
> This patch is inspired by the following:
> * Existing LDM/STM patterns and peephole optimizations.
> * Sameera's patches for prolog/epilog using LDRD/STRD:
> http://gcc.gnu.org/ml/gcc-patches/2011-10/msg00856.html
> * Carrot's patch for merging LDR/STR into LDRD/STRD, which was
> unfortunately
> breaking the build and had to be reverted. In particular, test files
> gcc.target/arm/pr45335*.c are from Carrot's patch.
> http://gcc.gnu.org/ml/gcc-patches/2011-06/msg01250.html
> 
> 
> The patterns introduced by this patch use a new constraint, defined as
> follows:
> +(define_register_constraint "q" "TARGET_ARM && TARGET_LDRD ? CORE_REGS
> :
> GENERAL_REGS"
> + "@internal In ARM state with LDRD support, core registers, otherwise
> general registers.")
> 
> Register class CORE_REGS consists of registers r0-r15. Register class
> GENERAL_REGS consists of registers r0-12,r14,r15. The difference is
> that
> GENERAL_REGS class does not contain r13, which is the stack pointer
> register
> (SP). Therefore, in Thumb mode, "q" constraint is equivalent to "r"
> (which
> stands for GENERAL_REGS), and in ARM mode, "q" constraint also allows
> SP.
> 
> The "q" constraint is used in patterns for LDRD/STRD. In Thumb mode, SP
> is
> not allowed as the destination register in LDRD/STRD. In ARM mode only,
> the
> pair of registers IP and SP is allowed in LDRD/STRD. The "q" constraint
> allows us to treat these two cases uniformly in the patterns, without
> missing opportunities for generating LDRD/STRD. It is not common for SP
> to
> be written to memory or read from memory, but it happens for example in
> some
> regression tests for builtins that create call chains.
> 
> 
> gcc/ChangeLog
> 
> 2011-10-28  Greta Yorsh  <Greta.Yorsh@arm.com>
> 
>         * config/arm/arm.md: Include ldrdstrd.md.
>         * config/arm/ldrdstrd0.md: New file. Adds define_insn and
> peepholes
> for Thumb mode.
>         * config/arm/predicates.md (arm_hard_core_register_operand):
> New
> predicate.
>         * config/arm/constraints.md (q): New constraint.
>         * config/arm/arm-protos.h (bad_operands_ldrd_strd): New
> prototype.
>         (gen_operands_ldrd_strd) New prototype.
>         (gen_operands_const_strd) New prototype.
>         * config/arm/arm.c (bad_offset_ldrd_strd): New function.
>         (bad_operands_ldrd_strd): New function.
>         (bad_mem_for_ldrd_strd): New function.
>         (gen_operands_ldrd_strd): New function.
>         (gen_operands_const_strd): New function.
>         (find_free_regs_for_arm_const_strd): New function.
> 
> gcc/testsuite/ChangeLog
> 
> 2011-10-28  Carrot Wei  <Carrot@google.com>
>                 Greta Yorsh  <Greta.Yorsh@arm.com>
> 
>         PR target/45335
>         * gcc.target/arm/pr45335.c: New file.
>         * gcc.target/arm/pr45335-2.c: New file.
>         * gcc.target/arm/pr45335-3.c: New file.
> 
>         * gcc.target/arm/pr40457-3.c: Update to accept new compiler
> output.
>         * gcc.target/arm/pr40457-2.c: Likewise.
>         * gcc.target/arm/pr40457-1.c: Likewise.
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