Message ID | 20200721182649.mrhv4mk2qgigs7tv@jozef-acer-manjaro |
---|---|
State | New |
Headers | show |
Series | MSP430: Improve code-generation for shift instructions | expand |
Jozef Lawrynowicz <jozef.l@mittosystems.com> writes: > diff --git a/gcc/expmed.c b/gcc/expmed.c > index e7c03fbf92c..d3a1735d39e 100644 > --- a/gcc/expmed.c > +++ b/gcc/expmed.c > @@ -4086,9 +4086,12 @@ expand_sdiv_pow2 (scalar_int_mode mode, rtx op0, HOST_WIDE_INT d) > { > temp = gen_reg_rtx (mode); > temp = emit_store_flag (temp, LT, op0, const0_rtx, mode, 0, 1); > - temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX, > - 0, OPTAB_LIB_WIDEN); > - return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0); > + if (temp != NULL_RTX) > + { > + temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX, > + 0, OPTAB_LIB_WIDEN); > + return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0); > + } > } > > if (HAVE_conditional_move > @@ -4122,17 +4125,20 @@ expand_sdiv_pow2 (scalar_int_mode mode, rtx op0, HOST_WIDE_INT d) > > temp = gen_reg_rtx (mode); > temp = emit_store_flag (temp, LT, op0, const0_rtx, mode, 0, -1); > - if (GET_MODE_BITSIZE (mode) >= BITS_PER_WORD > - || shift_cost (optimize_insn_for_speed_p (), mode, ushift) > - > COSTS_N_INSNS (1)) > - temp = expand_binop (mode, and_optab, temp, gen_int_mode (d - 1, mode), > - NULL_RTX, 0, OPTAB_LIB_WIDEN); > - else > - temp = expand_shift (RSHIFT_EXPR, mode, temp, > - ushift, NULL_RTX, 1); > - temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX, > - 0, OPTAB_LIB_WIDEN); > - return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0); > + if (temp != NULL_RTX) > + { > + if (GET_MODE_BITSIZE (mode) >= BITS_PER_WORD > + || shift_cost (optimize_insn_for_speed_p (), mode, ushift) > + > COSTS_N_INSNS (1)) > + temp = expand_binop (mode, and_optab, temp, gen_int_mode (d - 1, mode), Long line. OK otherwise, thanks. I guess these failed attempts will leave a few unused temporary registers around (from the gen_reg_rtxes) but it's going to be hard to avoid that in a clean way. Richard > + NULL_RTX, 0, OPTAB_LIB_WIDEN); > + else > + temp = expand_shift (RSHIFT_EXPR, mode, temp, > + ushift, NULL_RTX, 1); > + temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX, > + 0, OPTAB_LIB_WIDEN); > + return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0); > + } > } > > label = gen_label_rtx ();
diff --git a/gcc/expmed.c b/gcc/expmed.c index e7c03fbf92c..d3a1735d39e 100644 --- a/gcc/expmed.c +++ b/gcc/expmed.c @@ -4086,9 +4086,12 @@ expand_sdiv_pow2 (scalar_int_mode mode, rtx op0, HOST_WIDE_INT d) { temp = gen_reg_rtx (mode); temp = emit_store_flag (temp, LT, op0, const0_rtx, mode, 0, 1); - temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX, - 0, OPTAB_LIB_WIDEN); - return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0); + if (temp != NULL_RTX) + { + temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX, + 0, OPTAB_LIB_WIDEN); + return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0); + } } if (HAVE_conditional_move @@ -4122,17 +4125,20 @@ expand_sdiv_pow2 (scalar_int_mode mode, rtx op0, HOST_WIDE_INT d) temp = gen_reg_rtx (mode); temp = emit_store_flag (temp, LT, op0, const0_rtx, mode, 0, -1); - if (GET_MODE_BITSIZE (mode) >= BITS_PER_WORD - || shift_cost (optimize_insn_for_speed_p (), mode, ushift) - > COSTS_N_INSNS (1)) - temp = expand_binop (mode, and_optab, temp, gen_int_mode (d - 1, mode), - NULL_RTX, 0, OPTAB_LIB_WIDEN); - else - temp = expand_shift (RSHIFT_EXPR, mode, temp, - ushift, NULL_RTX, 1); - temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX, - 0, OPTAB_LIB_WIDEN); - return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0); + if (temp != NULL_RTX) + { + if (GET_MODE_BITSIZE (mode) >= BITS_PER_WORD + || shift_cost (optimize_insn_for_speed_p (), mode, ushift) + > COSTS_N_INSNS (1)) + temp = expand_binop (mode, and_optab, temp, gen_int_mode (d - 1, mode), + NULL_RTX, 0, OPTAB_LIB_WIDEN); + else + temp = expand_shift (RSHIFT_EXPR, mode, temp, + ushift, NULL_RTX, 1); + temp = expand_binop (mode, add_optab, temp, op0, NULL_RTX, + 0, OPTAB_LIB_WIDEN); + return expand_shift (RSHIFT_EXPR, mode, temp, logd, NULL_RTX, 0); + } } label = gen_label_rtx ();
MSP430 does not support have any store-flag instructions, so emit_store_flag can return NULL_RTX. Catch the NULL_RTX in expmed.c:expand_sdiv_pow2. Successfully regtested on trunk for x86_64-pc-linux-gnu and msp430-elf. Ok to apply? From cb0f8219ac90229c0336281d73f511c107c877d3 Mon Sep 17 00:00:00 2001 From: Jozef Lawrynowicz <jozef.l@mittosystems.com> Date: Wed, 15 Jul 2020 11:19:31 +0100 Subject: [PATCH 2/3] expmed: Fix possible use of NULL_RTX return value from emit_store_flag MSP430 does not support have any store-flag instructions, so emit_store_flag can return NULL_RTX. Catch the NULL_RTX in expmed.c:expand_sdiv_pow2. gcc/ChangeLog: * expmed.c (expand_sdiv_pow2): Check return value from emit_store_flag is not NULL_RTX before use. --- gcc/expmed.c | 34 ++++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-)