From a5a6598d5b1d29741993371310c0bb8ca57e190c Mon Sep 17 00:00:00 2001 From: Eric Botcazou Date: Fri, 14 Oct 2022 11:52:04 +0200 Subject: [PATCH] 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. --- 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 aca925befe15..a47537365a8c 100644 --- a/gcc/config/sparc/sparc.cc +++ b/gcc/config/sparc/sparc.cc @@ -6050,6 +6050,9 @@ 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 { @@ -6064,13 +6067,7 @@ 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 @@ -6166,8 +6163,8 @@ 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) { @@ -6254,6 +6251,9 @@ 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) @@ -6304,15 +6304,15 @@ 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))); -- 2.47.2