Mesa (master): draw: Respect pipe_vertex_buffer:: max_index in llvm generated code.

[Jose Fonseca]

Module: Mesa
Branch: master
Commit: 4dd1a568404dcf068cb111db04bb6e904b91d7bd
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=4dd1a568404dcf068cb111db04bb6e904b91d7bd

Author: José Fonseca <jfonseca at vmware.com>
Date:   Sun Apr 25 21:43:49 2010 +0100

draw: Respect pipe_vertex_buffer::max_index in llvm generated code.

Everybody should respect max_index, specially llvm generated code, which
likes to eat vertices 4 at a time, so it may end up chew a bit a bit more
than actually exists.

---

 src/gallium/auxiliary/draw/draw_llvm.c |   12 +++++++++---
 src/gallium/auxiliary/draw/draw_llvm.h |    5 ++++-
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/gallium/auxiliary/draw/draw_llvm.c b/src/gallium/auxiliary/draw/draw_llvm.c
index 936753f..703b46b 100644
--- a/src/gallium/auxiliary/draw/draw_llvm.c
+++ b/src/gallium/auxiliary/draw/draw_llvm.c
@@ -286,10 +286,16 @@ generate_fetch(LLVMBuilderRef builder,
    LLVMValueRef vbuffer_ptr = LLVMBuildGEP(builder, vbuffers_ptr,
                                            &indices, 1, "");
    LLVMValueRef vb_stride = draw_jit_vbuffer_stride(builder, vbuf);
+   LLVMValueRef vb_max_index = draw_jit_vbuffer_max_index(builder, vbuf);
    LLVMValueRef vb_buffer_offset = draw_jit_vbuffer_offset(builder, vbuf);
-   LLVMValueRef stride = LLVMBuildMul(builder,
-                                      vb_stride,
-                                      index, "");
+   LLVMValueRef cond;
+   LLVMValueRef stride;
+
+   cond = LLVMBuildICmp(builder, LLVMIntULE, index, vb_max_index, "");
+
+   index = LLVMBuildSelect(builder, cond, index, vb_max_index, "");
+
+   stride = LLVMBuildMul(builder, vb_stride, index, "");
 
    vbuffer_ptr = LLVMBuildLoad(builder, vbuffer_ptr, "vbuffer");
 
diff --git a/src/gallium/auxiliary/draw/draw_llvm.h b/src/gallium/auxiliary/draw/draw_llvm.h
index 28b9044..20f4f3d 100644
--- a/src/gallium/auxiliary/draw/draw_llvm.h
+++ b/src/gallium/auxiliary/draw/draw_llvm.h
@@ -78,7 +78,10 @@ struct draw_jit_context
 #define draw_jit_vbuffer_stride(_builder, _ptr)         \
    lp_build_struct_get(_builder, _ptr, 0, "stride")
 
-#define draw_jit_vbuffer_offset(_builder, _ptr)                 \
+#define draw_jit_vbuffer_max_index(_builder, _ptr)      \
+   lp_build_struct_get(_builder, _ptr, 1, "max_index")
+
+#define draw_jit_vbuffer_offset(_builder, _ptr)         \
    lp_build_struct_get(_builder, _ptr, 2, "buffer_offset")