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From: Eric Botcazou <ebotcazou@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-3296] Fix PR target/107248 Date: Fri, 14 Oct 2022 09:56:46 +0000 (GMT) [thread overview] Message-ID: <20221014095646.EAB50385800A@sourceware.org> (raw) https://gcc.gnu.org/g:e39b170695a161feba7401b7d21d824db9ee1f8f commit r13-3296-ge39b170695a161feba7401b7d21d824db9ee1f8f Author: Eric Botcazou <ebotcazou@adacore.com> Date: Fri Oct 14 11:52:04 2022 +0200 Fix PR target/107248 This is the infamous PR rtl-optimization/38644 rearing its ugly head for leaf functions on SPARC more than a decade later... Richard E.'s generic solution has never been implemented so let's do as other RISC back-ends did. gcc/ PR target/107248 * config/sparc/sparc.cc (sparc_expand_prologue): Emit a frame blockage for leaf functions. (sparc_flat_expand_prologue): Emit frame instead of full blockage. (sparc_expand_epilogue): Emit a frame blockage for leaf functions. (sparc_flat_expand_epilogue): Emit frame instead of full blockage. Diff: --- gcc/config/sparc/sparc.cc | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/gcc/config/sparc/sparc.cc b/gcc/config/sparc/sparc.cc index c72c38e1999..10c0f52d3d9 100644 --- a/gcc/config/sparc/sparc.cc +++ b/gcc/config/sparc/sparc.cc @@ -6051,6 +6051,9 @@ sparc_expand_prologue (void) } RTX_FRAME_RELATED_P (insn) = 1; + + /* Ensure no memory access is done before the frame is established. */ + emit_insn (gen_frame_blockage ()); } else { @@ -6065,13 +6068,7 @@ sparc_expand_prologue (void) /* %sp is not the CFA register anymore. */ emit_insn (gen_stack_pointer_inc (GEN_INT (4096 - size))); - /* Make sure no %fp-based store is issued until after the frame is - established. The offset between the frame pointer and the stack - pointer is calculated relative to the value of the stack pointer - at the end of the function prologue, and moving instructions that - access the stack via the frame pointer between the instructions - that decrement the stack pointer could result in accessing the - register window save area, which is volatile. */ + /* Likewise. */ emit_insn (gen_frame_blockage ()); } else @@ -6167,8 +6164,8 @@ sparc_flat_expand_prologue (void) } RTX_FRAME_RELATED_P (insn) = 1; - /* Ensure nothing is scheduled until after the frame is established. */ - emit_insn (gen_blockage ()); + /* Ensure no memory access is done before the frame is established. */ + emit_insn (gen_frame_blockage ()); if (frame_pointer_needed) { @@ -6255,6 +6252,9 @@ sparc_expand_epilogue (bool for_eh) ; /* do nothing. */ else if (sparc_leaf_function_p) { + /* Ensure no memory access is done after the frame is destroyed. */ + emit_insn (gen_frame_blockage ()); + if (size <= 4096) emit_insn (gen_stack_pointer_inc (GEN_INT (size))); else if (size <= 8192) @@ -6305,15 +6305,15 @@ sparc_flat_expand_epilogue (bool for_eh) ; /* do nothing. */ else if (frame_pointer_needed) { - /* Make sure the frame is destroyed after everything else is done. */ - emit_insn (gen_blockage ()); + /* Ensure no memory access is done after the frame is destroyed. */ + emit_insn (gen_frame_blockage ()); emit_move_insn (stack_pointer_rtx, gen_rtx_REG (Pmode, 1)); } else { /* Likewise. */ - emit_insn (gen_blockage ()); + emit_insn (gen_frame_blockage ()); if (size <= 4096) emit_insn (gen_stack_pointer_inc (GEN_INT (size)));
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