[PATCH, HSA] fix emission of HSAIL for builtins

[Martin LiÅka <mliska at suse dot cz>]

Hello.

Following patch has been just applied to HSA branch and is responsible
for correct emission of builtins. As HSAIL can support approximation
for builtins like 'sin', we emit these if unsafe_math_optimization flag
is enabled. Otherwise direct call instructions are emitted.

I would like to install the patch to trunk as soon as initial patch set
will be merged.

Thanks,
Martin

>From 110a6e64af6c5ad7c925e7ef3837f3685e07fe12 Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Thu, 5 Nov 2015 16:59:07 +0100
Subject: [PATCH 2/2] HSA: fix emission of HSAIL for builtins

gcc/ChangeLog:

2015-11-05  Martin Liska  <mliska@suse.cz>

	* hsa-gen.c (gen_hsa_unaryop_builtin_call): New function.
	(gen_hsa_unaryop_or_call_for_builtin): Likewise.
	(gen_hsa_insns_for_call): Use these aforementioned functions
	to correctly dispatch between creation of a function call
	and direct usage of an HSAIL instruction.
---
 gcc/hsa-gen.c | 57 +++++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 41 insertions(+), 16 deletions(-)

diff --git a/gcc/hsa-gen.c b/gcc/hsa-gen.c
index 48c4254..300bee6 100644
--- a/gcc/hsa-gen.c
+++ b/gcc/hsa-gen.c
@@ -4073,6 +4073,36 @@ gen_hsa_unaryop_for_builtin (int opcode, gimple *stmt, hsa_bb *hbb)
   gen_hsa_unary_operation (opcode, dest, op, hbb);
 }
 
+/* Helper functions to create a call to standard library if LHS of the
+   STMT is used.  HBB is the HSA BB to which the instruction should be
+   added.  */
+
+static void
+gen_hsa_unaryop_builtin_call (gimple *stmt, hsa_bb *hbb)
+{
+  tree lhs = gimple_call_lhs (stmt);
+  if (!lhs)
+    return;
+
+  gen_hsa_insns_for_direct_call (stmt, hbb);
+}
+
+/* Helper functions to create a single unary HSA operations out of calls to
+   builtins (if unsafe math optimizations are enable). Otherwise, create
+   a call to standard library function.
+   OPCODE is the HSA operation to be generated.  STMT is a gimple
+   call to a builtin.  HBB is the HSA BB to which the instruction should be
+   added.  Note that nothing will be created if STMT does not have a LHS.  */
+
+static void
+gen_hsa_unaryop_or_call_for_builtin (int opcode, gimple *stmt, hsa_bb *hbb)
+{
+  if (flag_unsafe_math_optimizations)
+    gen_hsa_unaryop_for_builtin (opcode, stmt, hbb);
+  else
+    gen_hsa_unaryop_builtin_call (stmt, hbb);
+}
+
 /* Generate HSA address corresponding to a value VAL (as opposed to a memory
    reference tree), for example an SSA_NAME or an ADDR_EXPR.  HBB is the HSA BB
    to which the instruction should be added.  */
@@ -4345,7 +4375,6 @@ gen_hsa_insns_for_call (gimple *stmt, hsa_bb *hbb)
 
     case BUILT_IN_SQRT:
     case BUILT_IN_SQRTF:
-      /* TODO: Perhaps produce BRIG_OPCODE_NSQRT with -ffast-math?  */
       gen_hsa_unaryop_for_builtin (BRIG_OPCODE_SQRT, stmt, hbb);
       break;
 
@@ -4355,31 +4384,27 @@ gen_hsa_insns_for_call (gimple *stmt, hsa_bb *hbb)
       break;
 
     case BUILT_IN_COS:
+    case BUILT_IN_SIN:
+    case BUILT_IN_EXP2:
+    case BUILT_IN_LOG2:
+      /* HSAIL does not provide an instruction for double argument type.  */
+      gen_hsa_unaryop_builtin_call (stmt, hbb);
+      break;
+
     case BUILT_IN_COSF:
-      /* FIXME: Using the native instruction may not be precise enough.
-	 Perhaps only allow if using -ffast-math?  */
-      gen_hsa_unaryop_for_builtin (BRIG_OPCODE_NCOS, stmt, hbb);
+      gen_hsa_unaryop_or_call_for_builtin (BRIG_OPCODE_NCOS, stmt, hbb);
       break;
 
-    case BUILT_IN_EXP2:
     case BUILT_IN_EXP2F:
-      /* FIXME: Using the native instruction may not be precise enough.
-	 Perhaps only allow if using -ffast-math?  */
-      gen_hsa_unaryop_for_builtin (BRIG_OPCODE_NEXP2, stmt, hbb);
+      gen_hsa_unaryop_or_call_for_builtin (BRIG_OPCODE_NEXP2, stmt, hbb);
       break;
 
-    case BUILT_IN_LOG2:
     case BUILT_IN_LOG2F:
-      /* FIXME: Using the native instruction may not be precise enough.
-	 Perhaps only allow if using -ffast-math?  */
-      gen_hsa_unaryop_for_builtin (BRIG_OPCODE_NLOG2, stmt, hbb);
+      gen_hsa_unaryop_or_call_for_builtin (BRIG_OPCODE_NLOG2, stmt, hbb);
       break;
 
-    case BUILT_IN_SIN:
     case BUILT_IN_SINF:
-      /* FIXME: Using the native instruction may not be precise enough.
-	 Perhaps only allow if using -ffast-math?  */
-      gen_hsa_unaryop_for_builtin (BRIG_OPCODE_NSIN, stmt, hbb);
+      gen_hsa_unaryop_or_call_for_builtin (BRIG_OPCODE_NSIN, stmt, hbb);
       break;
 
     case BUILT_IN_ATOMIC_LOAD_1:
-- 
2.6.2