On Mon, Sep 2, 2013 at 9:03 AM, bin.cheng <bin.ch...@arm.com> wrote: > Hi, > For now set_autoinc_for_original_candidates only searches auto-inc uses > before candidate's increment, causing pre-increment opportunities missed for > original candidates. This is a straightforward fix by searching after > candidate's increment too. > > The patch also includes a test case to illustrate the problem. Without the > patch, assembly of the test is: > foo: > @ args = 0, pretend = 0, frame = 0 > @ frame_needed = 0, uses_anonymous_args = 0 > @ link register save eliminated. > movw r3, #:lower16:__ctype_ptr__ > ldrb r2, [r0] @ zero_extendqisi2 > movt r3, #:upper16:__ctype_ptr__ > ldr r1, [r3] > adds r3, r1, r2 > ldrb r3, [r3, #1] @ zero_extendqisi2 > lsls r3, r3, #29 > bmi .L2 > adds r3, r0, #1 > .L3: > mov r0, r3 > adds r3, r3, #1 > ldrb r2, [r0] @ zero_extendqisi2 > add r2, r2, r1 > ldrb r2, [r2, #1] @ zero_extendqisi2 > lsls r2, r2, #29 > bpl .L3 > .L2: > bx lr > .size foo, .-foo > > Which can be optimized into below: > foo: > @ args = 0, pretend = 0, frame = 0 > @ frame_needed = 0, uses_anonymous_args = 0 > @ link register save eliminated. > movw r3, #:lower16:__ctype_ptr__ > ldrb r1, [r0] @ zero_extendqisi2 > movt r3, #:upper16:__ctype_ptr__ > ldr r2, [r3] > adds r3, r2, r1 > ldrb r3, [r3, #1] @ zero_extendqisi2 > lsls r1, r3, #29 > bmi .L2 > .L3: > ldrb r3, [r0, #1]! @ zero_extendqisi2 > add r3, r3, r2 > ldrb r3, [r3, #1] @ zero_extendqisi2 > lsls r3, r3, #29 > bpl .L3 > .L2: > bx lr > .size foo, .-foo > > Bootstrapped and tested on arm a15, is it OK?
Ok. Thanks, Richard. > Thanks. > bin > > 2013-09-02 Bin Cheng <bin.ch...@arm.com> > > * tree-ssa-loop-ivopts.c (set_autoinc_for_original_candidates): > Find auto-increment use both before and after candidate. > > gcc/testsuite/ChangeLog > 2013-09-02 Bin Cheng <bin.ch...@arm.com> > > * gcc.target/arm/ivopts-orig_biv-inc.c: New test.
