ping^2 ?
On Sun, 3 Nov 2019 at 16:07, Christophe Lyon <christophe.l...@linaro.org> wrote: > > Ping? > > https://gcc.gnu.org/ml/gcc-patches/2019-10/msg01356.html > > On Fri, 18 Oct 2019 at 15:18, Christophe Lyon > <christophe.l...@linaro.org> wrote: > > > > Hi, > > > > This patch extends support for -mpure-code to all thumb-1 processors, > > by removing the need for MOVT. > > > > Symbol addresses are built using upper8_15, upper0_7, lower8_15 and > > lower0_7 relocations, and constants are built using sequences of > > movs/adds and lsls instructions. > > > > The extension of the *thumb1_movhf pattern uses always the same size > > (6) although it can emit a shorter sequence when possible. This is > > similar to what *arm32_movhf already does. > > > > CASE_VECTOR_PC_RELATIVE is now false with -mpure-code, to avoid > > generating invalid assembly code with differences from symbols from > > two different sections (the difference cannot be computed by the > > assembler). > > > > Tests pr45701-[12].c needed a small adjustment to avoid matching > > upper8_15 when looking for the r8 register. > > > > Test no-literal-pool.c is augmented with __fp16, so it now uses > > -mfp16-format=ieee. > > > > Test thumb1-Os-mult.c generates an inline code sequence with > > -mpure-code and computes the multiplication by using a sequence of > > add/shift rather than using the multiply instruction, so we skip it in > > presence of -mpure-code. > > > > With -mcpu=cortex-m0, the pure-code/no-literal-pool.c fails because > > code like: > > static char *p = "Hello World"; > > char * > > testchar () > > { > > return p + 4; > > } > > generates 2 indirections (I removed non-essential directives/code) > > .section .rodata > > .LC0: > > .ascii "Hello World\000" > > .data > > p: > > .word .LC0 > > .section .rodata > > .LC2: > > .word p > > .section .text,"0x20000006",%progbits > > testchar: > > push {r7, lr} > > add r7, sp, #0 > > movs r3, #:upper8_15:#.LC2 > > lsls r3, #8 > > adds r3, #:upper0_7:#.LC2 > > lsls r3, #8 > > adds r3, #:lower8_15:#.LC2 > > lsls r3, #8 > > adds r3, #:lower0_7:#.LC2 > > ldr r3, [r3] > > ldr r3, [r3] > > adds r3, r3, #4 > > movs r0, r3 > > mov sp, r7 > > @ sp needed > > pop {r7, pc} > > > > By contrast, when using -mcpu=cortex-m4, the code looks like: > > .section .rodata > > .LC0: > > .ascii "Hello World\000" > > .data > > p: > > .word .LC0 > > testchar: > > push {r7} > > add r7, sp, #0 > > movw r3, #:lower16:p > > movt r3, #:upper16:p > > ldr r3, [r3] > > adds r3, r3, #4 > > mov r0, r3 > > mov sp, r7 > > pop {r7} > > bx lr > > > > I haven't found yet how to make code for cortex-m0 apply upper/lower > > relocations to "p" instead of .LC2. The current code looks functional, > > but could be improved. > > > > OK as-is? > > > > Thanks, > > > > Christophe
