diff options
Diffstat (limited to 'source/slang/ir.cpp')
| -rw-r--r-- | source/slang/ir.cpp | 54 |
1 files changed, 53 insertions, 1 deletions
diff --git a/source/slang/ir.cpp b/source/slang/ir.cpp index cc3350aef..a66b26e93 100644 --- a/source/slang/ir.cpp +++ b/source/slang/ir.cpp @@ -2939,6 +2939,11 @@ namespace Slang dump(context, "\n[__vulkanHitAttributes]"); } break; + case kIRDecorationOp_ReadNone: + { + dump(context, "\n[__readNone]"); + } + break; } } } @@ -3521,7 +3526,30 @@ namespace Slang return true; case kIROp_Call: - // This is the most interesting. + { + // In the general case, a function call must be assumed to + // have almost arbitrary side effects. + // + // However, it is possible that the callee can be identified, + // and it may be a function with an attribute that explicitly + // limits the side effects it is allowed to have. + // + // For now, we will explicitly check for the `[__readNone]` + // attribute, which was used to mark functions that compute + // their result strictly as a function of the arguments (and + // not anything they point to, or other non-argument state). + // Calls to such functions cannot have side effects (except + // for things like stack overflow that abstract language models + // tend to ignore), and can be subject to dead code elimination, + // common subexpression elimination, etc. + // + auto call = cast<IRCall>(this); + auto callee = getResolvedInstForDecorations(call->getCallee()); + if(callee->findDecoration<IRReadNoneDecoration>()) + { + return false; + } + } return true; case kIROp_Nop: @@ -5371,6 +5399,12 @@ namespace Slang } break; + case kIRDecorationOp_ReadNone: + { + context->builder->addDecoration<IRReadNoneDecoration>(clonedValue); + } + break; + default: // Don't clone any decorations we don't understand. break; @@ -6005,6 +6039,24 @@ namespace Slang return val; } + IRInst* getResolvedInstForDecorations(IRInst* inst) + { + IRInst* candidate = inst; + while(auto specInst = as<IRSpecialize>(candidate)) + { + auto genericInst = as<IRGeneric>(specInst->getBase()); + if(!genericInst) + break; + + auto returnVal = findGenericReturnVal(genericInst); + if(!returnVal) + break; + + candidate = returnVal; + } + return candidate; + } + bool isDefinition( IRGlobalValue* inVal) { |