| Message ID | 6538840.4Rt7JtybtJ@polaris |
|---|---|
| State | New |
| Headers | show |
On Sun, Nov 11, 2012 at 7:01 AM, Eric Botcazou <ebotcazou@adacore.com> wrote: >> This patch also handles SIGN_EXTEND. Tested on Linux/x32. OK to >> install? > > I'd cautious here, that's uncharted territory and the SIGN_EXTEND case isn't > covered by your testing. > >> 2012-11-10 H.J. Lu <hongjiu.lu@intel.com> >> >> PR middle-end/55247 >> PR middle-end/55259 >> * emit-rtl.c (adjust_address_1): Handle ZERO_EXTEND and >> SIGN_EXTEND. > > The new transformation is: > (zero_extend ADDR) + CONST_INT -> (zero_extend (ADDR + CONST_INT)) > but in convert_memory_address_addr_space we do the opposite: > (zero_extend (ADDR + CONST_INT)) -> (zero_extend ADDR) + CONST_INT > > Which one is the canonical form in the end? > >> @@ -2109,6 +2111,20 @@ adjust_address_1 (rtx memref, enum machine_mode mode, >> HOST_WIDE_INT offset, addr = gen_rtx_LO_SUM (address_mode, XEXP (addr, 0), >> plus_constant (address_mode, >> XEXP (addr, 1), offset)); >> + /* We permute zero/sign-extension and addition operation only if >> + converting the constant does not change it. */ >> + else if ((GET_CODE (addr) == ZERO_EXTEND >> + || GET_CODE (addr) == SIGN_EXTEND) >> + && (x = GEN_INT (offset), >> + x == convert_memory_address_addr_space (address_mode, >> + x, >> + attrs.addrspace))) >> + { >> + enum rtx_code code = GET_CODE (addr); >> + addr = XEXP (addr, 0); >> + addr = plus_constant (GET_MODE (addr), addr, offset); >> + addr = gen_rtx_fmt_e (code, address_mode, addr); >> + } > > You need to test the truncation here, not the extension. Moreover, the > transformation is valid only under a no-overflow assumption, so I think we > need to explicitly request pointer_mode (or else restrict the transformation > to small offsets). > >> diff --git a/gcc/recog.c b/gcc/recog.c >> index ee68e30..a916ef6 100644 >> --- a/gcc/recog.c >> +++ b/gcc/recog.c >> @@ -1934,15 +1934,22 @@ int >> offsettable_address_addr_space_p (int strictp, enum machine_mode mode, rtx >> y, addr_space_t as) >> { >> - enum rtx_code ycode = GET_CODE (y); >> + enum rtx_code ycode; >> rtx z; >> - rtx y1 = y; >> + rtx y1; >> rtx *y2; >> int (*addressp) (enum machine_mode, rtx, addr_space_t) = >> (strictp ? strict_memory_address_addr_space_p >> >> : memory_address_addr_space_p); >> >> unsigned int mode_sz = GET_MODE_SIZE (mode); >> >> + /* Allow zero-extended or sign-extended address. */ >> + if (GET_CODE (y) == ZERO_EXTEND || GET_CODE (y) == SIGN_EXTEND) >> + y = XEXP (y, 0); >> + >> + ycode = GET_CODE (y); >> + y1 = y; >> + >> if (CONSTANT_ADDRESS_P (y)) >> return 1; > > That's not fully correct since you don't test the final form of the address. > You instead need to duplicate the adjust_address_1 change here: > > /* The offset added here is chosen as the maximum offset that > any instruction could need to add when operating on something > of the specified mode. We assume that if Y and Y+c are > valid addresses then so is Y+d for all 0<d<c. adjust_address will > go inside a LO_SUM here, so we do so as well. */ > if (GET_CODE (y) == LO_SUM > && mode != BLKmode > && mode_sz <= GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT) > z = gen_rtx_LO_SUM (GET_MODE (y), XEXP (y, 0), > plus_constant (GET_MODE (y), XEXP (y, 1), > mode_sz - 1)); > else > z = plus_constant (GET_MODE (y), y, mode_sz - 1); > > > Adjusted patch attached. > > -- > Eric Botcazou It fixes the problem. Can you check it in? Thanks.
> It fixes the problem. Can you check it in?
Done.
Index: emit-rtl.c =================================================================== --- emit-rtl.c (revision 193322) +++ emit-rtl.c (working copy) @@ -2071,10 +2071,12 @@ adjust_address_1 (rtx memref, enum machi rtx new_rtx; enum machine_mode address_mode; int pbits; - struct mem_attrs attrs, *defattrs; + struct mem_attrs attrs = *get_mem_attrs (memref), *defattrs; unsigned HOST_WIDE_INT max_align; - - attrs = *get_mem_attrs (memref); +#ifdef POINTERS_EXTEND_UNSIGNED + enum machine_mode pointer_mode + = targetm.addr_space.pointer_mode (attrs.addrspace); +#endif /* If there are no changes, just return the original memory reference. */ if (mode == GET_MODE (memref) && !offset @@ -2109,6 +2111,18 @@ adjust_address_1 (rtx memref, enum machi addr = gen_rtx_LO_SUM (address_mode, XEXP (addr, 0), plus_constant (address_mode, XEXP (addr, 1), offset)); +#ifdef POINTERS_EXTEND_UNSIGNED + /* If MEMREF is a ZERO_EXTEND from pointer_mode and the offset is valid + in that mode, we merge it into the ZERO_EXTEND. We take advantage of + the fact that pointers are not allowed to overflow. */ + else if (POINTERS_EXTEND_UNSIGNED > 0 + && GET_CODE (addr) == ZERO_EXTEND + && GET_MODE (XEXP (addr, 0)) == pointer_mode + && trunc_int_for_mode (offset, pointer_mode) == offset) + addr = gen_rtx_ZERO_EXTEND (address_mode, + plus_constant (pointer_mode, + XEXP (addr, 0), offset)); +#endif else addr = plus_constant (address_mode, addr, offset); } Index: recog.c =================================================================== --- recog.c (revision 193322) +++ recog.c (working copy) @@ -1943,6 +1943,9 @@ offsettable_address_addr_space_p (int st (strictp ? strict_memory_address_addr_space_p : memory_address_addr_space_p); unsigned int mode_sz = GET_MODE_SIZE (mode); +#ifdef POINTERS_EXTEND_UNSIGNED + enum machine_mode pointer_mode = targetm.addr_space.pointer_mode (as); +#endif if (CONSTANT_ADDRESS_P (y)) return 1; @@ -1992,6 +1995,15 @@ offsettable_address_addr_space_p (int st z = gen_rtx_LO_SUM (GET_MODE (y), XEXP (y, 0), plus_constant (GET_MODE (y), XEXP (y, 1), mode_sz - 1)); +#ifdef POINTERS_EXTEND_UNSIGNED + /* Likewise for a ZERO_EXTEND from pointer_mode. */ + else if (POINTERS_EXTEND_UNSIGNED > 0 + && GET_CODE (y) == ZERO_EXTEND + && GET_MODE (XEXP (y, 0)) == pointer_mode) + z = gen_rtx_ZERO_EXTEND (GET_MODE (y), + plus_constant (pointer_mode, XEXP (y, 0), + mode_sz - 1)); +#endif else z = plus_constant (GET_MODE (y), y, mode_sz - 1);