On Tue, Nov 8, 2022 at 6:07 PM Jakub Jelinek via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > On Fri, Nov 04, 2022 at 03:46:32PM +0800, Haochen Jiang via Gcc-patches wrote: > > We will take back the patches which add a new parameter on original > > builtin_prefetch and implement instruction prefetch on that. > > > > Also we consider that since we will only do that on specific backend, > > no need to add a new rtl for that. > > > > This patch will only support instructions prefetch for x86 backend. > > > > Regtested on x86_64-pc-linux-gnu. Ok for trunk? > > The gcc.target/i386/prefetchi-4.c testcase ICEs for me on i686-linux. > Can be reproduced even on x86_64, with: > ./cc1 -quiet -m32 -march=pentiumpro prefetchi-4.c -isystem include/ > during RTL pass: expand > prefetchi-4.c: In function ‘prefetch_test’: > prefetchi-4.c:11:3: internal compiler error: in gen_prefetch, at > config/i386/i386.md:23913 > 11 | __builtin_ia32_prefetch (p, 0, 3, 0); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 0x1b92416 gen_prefetch(rtx_def*, rtx_def*, rtx_def*) > ../../gcc/config/i386/i386.md:23913 > 0x141dcf3 ix86_expand_builtin(tree_node*, rtx_def*, rtx_def*, machine_mode, > int) > ../../gcc/config/i386/i386-expand.cc:13077 > 0x60deb4 expand_builtin(tree_node*, rtx_def*, rtx_def*, machine_mode, int) > ../../gcc/builtins.cc:7321 > 0x80803d expand_expr_real_1(tree_node*, rtx_def*, machine_mode, > expand_modifier, rtx_def**, bool) > ../../gcc/expr.cc:11865 > 0x7fa4d5 expand_expr_real(tree_node*, rtx_def*, machine_mode, > expand_modifier, rtx_def**, bool) > ../../gcc/expr.cc:9000 > 0x648c12 expand_expr > ../../gcc/expr.h:310 > 0x651c17 expand_call_stmt > ../../gcc/cfgexpand.cc:2831 > 0x655709 expand_gimple_stmt_1 > ../../gcc/cfgexpand.cc:3880 > 0x655d93 expand_gimple_stmt > ../../gcc/cfgexpand.cc:4044 > 0x65e061 expand_gimple_basic_block > ../../gcc/cfgexpand.cc:6096 > 0x660575 execute > ../../gcc/cfgexpand.cc:6822 > Please submit a full bug report, with preprocessed source (by using > -freport-bug). > Please include the complete backtrace with any bug report. > See <https://gcc.gnu.org/bugs/> for instructions. > > The ICE is on > gcc_assert (TARGET_3DNOW); > operands[2] = GEN_INT (3); > The expander has > "TARGET_3DNOW || TARGET_PREFETCH_SSE || TARGET_PRFCHW || TARGET_PREFETCHWT1" > condition and for write handles all those different ISAs, so gcc_assert > (TARGET_3DNOW); > at the end only asserts the obvious that the expander condition had to be > satisfied. But for !write, it only has: > if (TARGET_PREFETCH_SSE) > ; > else > { > gcc_assert (TARGET_3DNOW); > operands[2] = GEN_INT (3); > } > and here I don't understand how it can work, because if > !TARGET_3DNOW && !TARGET_PREFETCH_SSE, but > TARGET_PRFCHW || TARGET_PREFETCHWT1 > then it clearly ICEs. Both of the latter ISAs can be enabled/disabled > individually without dependencies. > > It is unclear what exactly changed though, because the prefetch pattern > has not changed, but it didn't ICE before that commit. We need to check the expander condition before gen_prefetch. > > Jakub >
-- BR, Hongtao
