From adcc547bfbef362067bb3b4e3aee75b287bc6189 Mon Sep 17 00:00:00 2001 From: Ilia Mirkin Date: Wed, 2 Dec 2015 00:38:21 -0500 Subject: [PATCH] nv50/ir: deal with loops with no breaks For example if there are only returns, the break bb will not end up part of the CFG. However there will have been a prebreak already emitted for it, and when hitting the RET that comes after, we will try to insert the current (i.e. break) BB into the graph even though it will be unreachable. This makes the SSA code sad. Signed-off-by: Ilia Mirkin Cc: "11.0 11.1" --- src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp index 08a73d79781..1d2caaba72f 100644 --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_tgsi.cpp @@ -2893,6 +2893,12 @@ Converter::handleInstruction(const struct tgsi_full_instruction *insn) bb->cfg.attach(&loopBB->cfg, Graph::Edge::BACK); } setPosition(reinterpret_cast(breakBBs.pop().u.p), true); + + // If the loop never breaks (e.g. only has RET's inside), then there + // will be no way to get to the break bb. However BGNLOOP will have + // already made a PREBREAK to it, so it must be in the CFG. + if (getBB()->cfg.incidentCount() == 0) + loopBB->cfg.attach(&getBB()->cfg, Graph::Edge::TREE); } break; case TGSI_OPCODE_BRK: -- 2.30.2