From: Juzhe-Zhong <juzhe.zhong@rivai.ai>
Date: Thu, 2 Nov 2023 11:30:23 +0000 (+0800)
Subject: RISC-V: Fix bug of AVL propagation PASS
X-Git-Tag: basepoints/gcc-15~5062
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f6284ef38701920865de3c9e18bb3f6068fde4d1;p=thirdparty%2Fgcc.git

RISC-V: Fix bug of AVL propagation PASS

A run FAIL suddenly shows up today to me:
FAIL: gcc.target/riscv/rvv/autovec/gather-scatter/mask_gather_load_run-11.c execution test

that I didn't have before.

After investigation, I realize that there is a bug in AVL propagtion PASS.

gcc/ChangeLog:

	* config/riscv/riscv-avlprop.cc
	(pass_avlprop::get_vlmax_ta_preferred_avl): Don't allow
	non-real insn AVL propation.
---

diff --git a/gcc/config/riscv/riscv-avlprop.cc b/gcc/config/riscv/riscv-avlprop.cc
index c59eb7f6fa32..bcd77a3047a0 100644
--- a/gcc/config/riscv/riscv-avlprop.cc
+++ b/gcc/config/riscv/riscv-avlprop.cc
@@ -266,6 +266,13 @@ pass_avlprop::get_vlmax_ta_preferred_avl (insn_info *insn) const
 	      def_info *def2 = dl.prev_def (use_insn);
 	      if (!def1 || !def2 || def1 != def2)
 		return NULL_RTX;
+	      /* For vectorized codes, we always use SELECT_VL/MIN_EXPR to
+		 calculate the loop len at the header of the loop.
+		 We only allow AVL propagation for real instruction for now.
+		 TODO: We may enhance it for intrinsic codes if it is necessary.
+	      */
+	      if (!def1->insn ()->is_real ())
+		return NULL_RTX;
 
 	      /* FIXME: We only all AVL propation within a block which should
 		 be totally enough for vectorized codes.