[BRIGFE] phsa-specific optimizations

Add flag -fassume-phsa that is on by default. If -fno-assume-phsa
is given, these optimizations are disabled.

With this flag, gccbrig can generate GENERIC that assumes we are
targeting a phsa-runtime based implementation, which allows us
to expose the work-item context accesses to retrieve WI IDs etc.
which helps optimizers.

First optimization that takes advantage of this is to get rid of
the setworkitemid calls whenever we have non-inlined calls that
use IDs internally.

Other optimizations added in this commit:

- expand absoluteid to similar level of simplicity as workitemid.
At the moment absoluteid is the best indexing ID to end up with
WG vectorization.
- propagate ID variables closer to their uses. This is mainly
to avoid known useless casts, which confuse at least scalar
evolution analysis.
- use signed long long for storing IDs. Unsigned integers have
defined wraparound semantics, which confuse at least scalar
evolution analysis, leading to unvectorizable WI loops.
- also refactor some BRIG function generation helpers to brig_function.
- no point in having the wi-loop as a for-loop. It's really
a do...while and SCEV can analyze it just fine still.
- add consts to ptrs etc. in BRIG builtin defs.
Improves optimization opportunities.
- add qualifiers to generated function parameters.
Const and restrict on the hidden local/private pointers,
the arg buffer and the context pointer help some optimizations.

From-SVN: r259957

4 files changed, 108 insertions, 34 deletions

diff --git a/libhsail-rt/ChangeLog b/libhsail-rt/ChangeLog
index 5ab9e85..17aeb6e4 100644
--- a/libhsail-rt/ChangeLog
+++ b/libhsail-rt/ChangeLog
@@ -1,5 +1,12 @@
 2018-05-04  Pekka Jääskeläinen  <pekka.jaaskelainen@parmance.com>
 
+	* include/internal/phsa-rt.h: Whitespace cleanup.
+	* include/internal/workitems.h: Store work item ID data to easily
+	accessible locations.
+	* rt/workitems.c: Same.
+
+2018-05-04  Pekka Jääskeläinen  <pekka.jaaskelainen@parmance.com>
+
 	* rt/workitems.c: Fix an alloca stack underflow.
 
 2018-04-18  David Malcolm  <dmalcolm@redhat.com>
diff --git a/libhsail-rt/include/internal/phsa-rt.h b/libhsail-rt/include/internal/phsa-rt.h
index d9db56c..c09f18d 100644
--- a/libhsail-rt/include/internal/phsa-rt.h
+++ b/libhsail-rt/include/internal/phsa-rt.h
@@ -54,7 +54,6 @@ typedef void (*gccbrigKernelFunc) (unsigned char *, void *, void *, uint32_t,
 */
 typedef struct
 {
-
   /* Data set by the HSA Runtime's kernel launcher.  */
   hsa_kernel_dispatch_packet_t *dp;
 
diff --git a/libhsail-rt/include/internal/workitems.h b/libhsail-rt/include/internal/workitems.h
index 73add28..0839853f 100644
--- a/libhsail-rt/include/internal/workitems.h
+++ b/libhsail-rt/include/internal/workitems.h
@@ -45,11 +45,6 @@
 
 typedef struct
 {
-  /* The group id of the currently executed WG.  */
-  size_t x;
-  size_t y;
-  size_t z;
-
   /* This is 1 in case there are more work groups to execute.
      If 0, the work-item threads should finish themselves.  */
   int more_wgs;
@@ -89,6 +84,16 @@ typedef struct
      stack frame.  Initialized to point outside the private segment.  */
   uint32_t alloca_frame_p;
 
+  /* The group id of the currently executed WG.  This is for fiber based
+     execution.  The group ids are duplicated also to the per WI context
+     struct for simplified single pointer access in the GCCBRIG produced
+     code.
+   */
+
+  uint32_t x;
+  uint32_t y;
+  uint32_t z;
+
 } PHSAWorkGroup;
 
 /* Data identifying a single work-item, passed to the work-item thread in case
@@ -96,17 +101,42 @@ typedef struct
 
 typedef struct
 {
+  /* NOTE: These members STARTing here should not be moved as they are
+     accessed directly by code emitted by BRIG FE.   */
+
+  /* The local id of the current WI. */
+
+  uint32_t x;
+  uint32_t y;
+  uint32_t z;
+
+  /* The group id of the currently executed WG.  */
+
+  uint32_t group_x;
+  uint32_t group_y;
+  uint32_t group_z;
+
+  /* The local size of a complete WG.  */
+
+  uint32_t wg_size_x;
+  uint32_t wg_size_y;
+  uint32_t wg_size_z;
+
+  /* The local size of the current WG.  */
+
+  uint32_t cur_wg_size_x;
+  uint32_t cur_wg_size_y;
+  uint32_t cur_wg_size_z;
+
+  /* NOTE: Fixed members END here.  */
+
   PHSAKernelLaunchData *launch_data;
   /* Identifies and keeps book of the currently executed WG of the WI swarm.  */
   volatile PHSAWorkGroup *wg;
-  /* The local id of the current WI.  */
-  size_t x;
-  size_t y;
-  size_t z;
 #ifdef HAVE_FIBERS
   fiber_t fiber;
 #endif
-} PHSAWorkItem;
+} __attribute__((packed)) PHSAWorkItem;
 
 
 #endif
diff --git a/libhsail-rt/rt/workitems.c b/libhsail-rt/rt/workitems.c
index 36c9169..c846350 100644
--- a/libhsail-rt/rt/workitems.c
+++ b/libhsail-rt/rt/workitems.c
@@ -107,11 +107,20 @@ phsa_work_item_thread (int arg0, int arg1)
 	 the current_work_group_* is set to point to the WG executed next.  */
       if (!wi->wg->more_wgs)
 	break;
+
+      wi->group_x = wg->x;
+      wi->group_y = wg->y;
+      wi->group_z = wg->z;
+
+      wi->cur_wg_size_x = __hsail_currentworkgroupsize (0, wi);
+      wi->cur_wg_size_y = __hsail_currentworkgroupsize (1, wi);
+      wi->cur_wg_size_z = __hsail_currentworkgroupsize (2, wi);
+
 #ifdef DEBUG_PHSA_RT
       printf (
 	"Running work-item %lu/%lu/%lu for wg %lu/%lu/%lu / %lu/%lu/%lu...\n",
-	wi->x, wi->y, wi->z, wg->x, wg->y, wg->z, l_data->wg_max_x,
-	l_data->wg_max_y, l_data->wg_max_z);
+	wi->x, wi->y, wi->z, wi->group_x, wi->group_y, wi->group_z,
+	l_data->wg_max_x, l_data->wg_max_y, l_data->wg_max_z);
 #endif
 
       if (wi->x < __hsail_currentworkgroupsize (0, wi)
@@ -180,6 +189,13 @@ phsa_work_item_thread (int arg0, int arg1)
 	  else
 	    wg->x++;
 #endif
+	  wi->group_x = wg->x;
+	  wi->group_y = wg->y;
+	  wi->group_z = wg->z;
+
+	  wi->cur_wg_size_x = __hsail_currentworkgroupsize (0, wi);
+	  wi->cur_wg_size_y = __hsail_currentworkgroupsize (1, wi);
+	  wi->cur_wg_size_z = __hsail_currentworkgroupsize (2, wi);
 
 	  /* Reinitialize the work-group barrier according to the new WG's
 	     size, which might not be the same as the previous ones, due
@@ -233,6 +249,7 @@ phsa_execute_wi_gang (PHSAKernelLaunchData *context, void *group_base_ptr,
   PHSAWorkItem *wi_threads = NULL;
   PHSAWorkGroup wg;
   size_t flat_wi_id = 0, x, y, z, max_x, max_y, max_z;
+  uint32_t group_x, group_y, group_z;
   fiber_barrier_t wg_start_barrier;
   fiber_barrier_t wg_completion_barrier;
   fiber_barrier_t wg_sync_barrier;
@@ -257,13 +274,13 @@ phsa_execute_wi_gang (PHSAKernelLaunchData *context, void *group_base_ptr,
   wg.initial_group_offset = group_local_offset;
 
 #ifdef EXECUTE_WGS_BACKWARDS
-  wg.x = context->wg_max_x - 1;
-  wg.y = context->wg_max_y - 1;
-  wg.z = context->wg_max_z - 1;
+  group_x = context->wg_max_x - 1;
+  group_y = context->wg_max_y - 1;
+  group_z = context->wg_max_z - 1;
 #else
-  wg.x = context->wg_min_x;
-  wg.y = context->wg_min_y;
-  wg.z = context->wg_min_z;
+  group_x = context->wg_min_x;
+  group_y = context->wg_min_y;
+  group_z = context->wg_min_z;
 #endif
 
   fiber_barrier_init (&wg_sync_barrier, wg_size);
@@ -290,6 +307,19 @@ phsa_execute_wi_gang (PHSAKernelLaunchData *context, void *group_base_ptr,
 	  PHSAWorkItem *wi = &wi_threads[flat_wi_id];
 	  wi->launch_data = context;
 	  wi->wg = &wg;
+
+	  wg.x = wi->group_x = group_x;
+	  wg.y = wi->group_y = group_y;
+	  wg.z = wi->group_z = group_z;
+
+	  wi->wg_size_x = context->dp->workgroup_size_x;
+	  wi->wg_size_y = context->dp->workgroup_size_y;
+	  wi->wg_size_z = context->dp->workgroup_size_z;
+
+	  wi->cur_wg_size_x = __hsail_currentworkgroupsize (0, wi);
+	  wi->cur_wg_size_y = __hsail_currentworkgroupsize (1, wi);
+	  wi->cur_wg_size_z = __hsail_currentworkgroupsize (2, wi);
+
 	  wi->x = x;
 	  wi->y = y;
 	  wi->z = z;
@@ -467,9 +497,17 @@ phsa_execute_work_groups (PHSAKernelLaunchData *context, void *group_base_ptr,
     for (wg_y = context->wg_min_y; wg_y < context->wg_max_y; ++wg_y)
       for (wg_x = context->wg_min_x; wg_x < context->wg_max_x; ++wg_x)
 	{
-	  wi.wg->x = wg_x;
-	  wi.wg->y = wg_y;
-	  wi.wg->z = wg_z;
+	  wi.group_x = wg_x;
+	  wi.group_y = wg_y;
+	  wi.group_z = wg_z;
+
+	  wi.wg_size_x = context->dp->workgroup_size_x;
+	  wi.wg_size_y = context->dp->workgroup_size_y;
+	  wi.wg_size_z = context->dp->workgroup_size_z;
+
+	  wi.cur_wg_size_x = __hsail_currentworkgroupsize (0, &wi);
+	  wi.cur_wg_size_y = __hsail_currentworkgroupsize (1, &wi);
+	  wi.cur_wg_size_z = __hsail_currentworkgroupsize (2, &wi);
 
 	  context->kernel (context->kernarg_addr, &wi, group_base_ptr,
 			   group_local_offset, private_base_ptr);
@@ -564,15 +602,15 @@ __hsail_workitemabsid (uint32_t dim, PHSAWorkItem *context)
     default:
     case 0:
       /* Overflow semantics in the case of WG dim > grid dim.  */
-      id = ((uint64_t) context->wg->x * dp->workgroup_size_x + context->x)
+      id = ((uint64_t) context->group_x * dp->workgroup_size_x + context->x)
 	   % dp->grid_size_x;
       break;
     case 1:
-      id = ((uint64_t) context->wg->y * dp->workgroup_size_y + context->y)
+      id = ((uint64_t) context->group_y * dp->workgroup_size_y + context->y)
 	   % dp->grid_size_y;
       break;
     case 2:
-      id = ((uint64_t) context->wg->z * dp->workgroup_size_z + context->z)
+      id = ((uint64_t) context->group_z * dp->workgroup_size_z + context->z)
 	   % dp->grid_size_z;
       break;
     }
@@ -590,15 +628,15 @@ __hsail_workitemabsid_u64 (uint32_t dim, PHSAWorkItem *context)
     default:
     case 0:
       /* Overflow semantics in the case of WG dim > grid dim.  */
-      id = ((uint64_t) context->wg->x * dp->workgroup_size_x + context->x)
+      id = ((uint64_t) context->group_x * dp->workgroup_size_x + context->x)
 	   % dp->grid_size_x;
       break;
     case 1:
-      id = ((uint64_t) context->wg->y * dp->workgroup_size_y + context->y)
+      id = ((uint64_t) context->group_y * dp->workgroup_size_y + context->y)
 	   % dp->grid_size_y;
       break;
     case 2:
-      id = ((uint64_t) context->wg->z * dp->workgroup_size_z + context->z)
+      id = ((uint64_t) context->group_z * dp->workgroup_size_z + context->z)
 	   % dp->grid_size_z;
       break;
     }
@@ -738,19 +776,19 @@ __hsail_currentworkgroupsize (uint32_t dim, PHSAWorkItem *wi)
     {
     default:
     case 0:
-      if ((uint64_t) wi->wg->x < dp->grid_size_x / dp->workgroup_size_x)
+      if ((uint64_t) wi->group_x < dp->grid_size_x / dp->workgroup_size_x)
 	wg_size = dp->workgroup_size_x; /* Full WG.  */
       else
 	wg_size = dp->grid_size_x % dp->workgroup_size_x; /* Partial WG.  */
       break;
     case 1:
-      if ((uint64_t) wi->wg->y < dp->grid_size_y / dp->workgroup_size_y)
+      if ((uint64_t) wi->group_y < dp->grid_size_y / dp->workgroup_size_y)
 	wg_size = dp->workgroup_size_y; /* Full WG.  */
       else
 	wg_size = dp->grid_size_y % dp->workgroup_size_y; /* Partial WG.  */
       break;
     case 2:
-      if ((uint64_t) wi->wg->z < dp->grid_size_z / dp->workgroup_size_z)
+      if ((uint64_t) wi->group_z < dp->grid_size_z / dp->workgroup_size_z)
 	wg_size = dp->workgroup_size_z; /* Full WG.  */
       else
 	wg_size = dp->grid_size_z % dp->workgroup_size_z; /* Partial WG.  */
@@ -798,11 +836,11 @@ __hsail_workgroupid (uint32_t dim, PHSAWorkItem *wi)
     {
     default:
     case 0:
-      return wi->wg->x;
+      return wi->group_x;
     case 1:
-      return wi->wg->y;
+      return wi->group_y;
     case 2:
-      return wi->wg->z;
+      return wi->group_z;
     }
 }