swr/rast: Fix alloca usage in jitter

Fix issue where temporary allocas were getting hoisted to function entry
unnecessarily. We now explicitly mark temporary allocas and skip hoisting
during the hoist pass. Shuold reduce stack usage.

Reviewed-by: Bruce Cherniak <bruce.cherniak@intel.com>

diff --git a/src/gallium/drivers/swr/rasterizer/jitter/builder.cpp b/src/gallium/drivers/swr/rasterizer/jitter/builder.cpp
index 53947c317e2684da04d6dafa4d12450b62a606a8..bd815606fbad51e7cbafa5b84f6def2df57443b1 100644 (file)
--- a/src/gallium/drivers/swr/rasterizer/jitter/builder.cpp
+++ b/src/gallium/drivers/swr/rasterizer/jitter/builder.cpp
@@ -111,4 +111,21 @@ namespace SwrJit
         mSimdVectorIntTy = ArrayType::get(mSimdInt32Ty, 4);
         mSimdVectorTRTy = ArrayType::get(mSimdFP32Ty, 5);
     }
+
+    /// @brief Mark this alloca as temporary to avoid hoisting later on
+    void Builder::SetTempAlloca(Value* inst)
+    {
+        AllocaInst* pAlloca = dyn_cast<AllocaInst>(inst);
+        SWR_ASSERT(pAlloca, "Unexpected non-alloca instruction");
+        MDNode* N = MDNode::get(JM()->mContext, MDString::get(JM()->mContext, "is_temp_alloca"));
+        pAlloca->setMetadata("is_temp_alloca", N);
+    }
+
+    bool Builder::IsTempAlloca(Value* inst)
+    {
+        AllocaInst* pAlloca = dyn_cast<AllocaInst>(inst);
+        SWR_ASSERT(pAlloca, "Unexpected non-alloca instruction");
+
+        return (pAlloca->getMetadata("is_temp_alloca") != nullptr);
+    }
 }

diff --git a/src/gallium/drivers/swr/rasterizer/jitter/builder.h b/src/gallium/drivers/swr/rasterizer/jitter/builder.h
index 4c79bab964b7047400a018616489e74f35c74d33..27a32bc3e3956f44af89e8e3f6622d0dd40529e4 100644 (file)
--- a/src/gallium/drivers/swr/rasterizer/jitter/builder.h
+++ b/src/gallium/drivers/swr/rasterizer/jitter/builder.h
@@ -96,6 +96,8 @@ namespace SwrJit
         Type*                mSimd32Int8Ty;
 
         void SetTargetWidth(uint32_t width);
+        void SetTempAlloca(Value* inst);
+        bool IsTempAlloca(Value* inst);
 
 #include "gen_builder.hpp"
 #include "gen_builder_meta.hpp"

diff --git a/src/gallium/drivers/swr/rasterizer/jitter/builder_mem.cpp b/src/gallium/drivers/swr/rasterizer/jitter/builder_mem.cpp
index c5f0b2b9fe0a97b7256cdfee05da720258cb7eb2..eccf0ad0d6d4922a4d63b0cc469d139d02e4e128 100644 (file)
--- a/src/gallium/drivers/swr/rasterizer/jitter/builder_mem.cpp
+++ b/src/gallium/drivers/swr/rasterizer/jitter/builder_mem.cpp
@@ -229,6 +229,7 @@ namespace SwrJit
 
             // store vSrc on the stack.  this way we can select between a valid load address and the vSrc address
             Value* vSrcPtr = ALLOCA(vSrc->getType());
+            SetTempAlloca(vSrcPtr);
             STORE(vSrc, vSrcPtr);
 
             vGather = UndefValue::get(VectorType::get(mDoubleTy, 4));