r300/compiler: Fix register allocator's handling of loops

NOTE: This is a candidate for the 7.9 branch.

diff --git a/src/mesa/drivers/dri/r300/compiler/radeon_pair_regalloc.c b/src/mesa/drivers/dri/r300/compiler/radeon_pair_regalloc.c
index 91524f5ec6863c5f5e2edd897e0922659e720722..3f880c88fa7f54b4d7da6e794567ba0abcd66233 100644 (file)
--- a/src/mesa/drivers/dri/r300/compiler/radeon_pair_regalloc.c
+++ b/src/mesa/drivers/dri/r300/compiler/radeon_pair_regalloc.c
@@ -66,10 +66,13 @@ struct regalloc_state {
        struct hardware_register * HwTemporary;
        unsigned int NumHwTemporaries;
        /**
-        * If an instruction is inside of a loop, end_loop will be the
-        * IP of the ENDLOOP instruction, otherwise end_loop will be 0
+        * If an instruction is inside of a loop, EndLoop will be the
+        * IP of the ENDLOOP instruction, and BeginLoop will be the IP
+        * of the BGNLOOP instruction.  Otherwise, EndLoop and BeginLoop
+        * will be -1.
         */
-       int end_loop;
+       int EndLoop;
+       int BeginLoop;
 };
 
 static void print_live_intervals(struct live_intervals * src)
@@ -180,11 +183,13 @@ static void scan_callback(void * data, struct rc_instruction * inst,
                reg->Used = 1;
                if (file == RC_FILE_INPUT)
                        reg->Live.Start = -1;
+               else if (s->BeginLoop >= 0)
+                       reg->Live.Start = s->BeginLoop;
                else
                        reg->Live.Start = inst->IP;
                reg->Live.End = inst->IP;
-       } else if (s->end_loop)
-               reg->Live.End = s->end_loop;
+       } else if (s->EndLoop >= 0)
+               reg->Live.End = s->EndLoop;
        else if (inst->IP > reg->Live.End)
                reg->Live.End = inst->IP;
 }
@@ -195,6 +200,8 @@ static void compute_live_intervals(struct radeon_compiler *c,
        memset(s, 0, sizeof(*s));
        s->C = c;
        s->NumHwTemporaries = c->max_temp_regs;
+       s->BeginLoop = -1;
+       s->EndLoop = -1;
        s->HwTemporary =
                memory_pool_malloc(&c->Pool,
                                   s->NumHwTemporaries * sizeof(struct hardware_register));
@@ -207,8 +214,10 @@ static void compute_live_intervals(struct radeon_compiler *c,
            inst = inst->Next) {
 
                /* For all instructions inside of a loop, the ENDLOOP
-                * instruction is used as the end of the live interval. */
-               if (inst->U.I.Opcode == RC_OPCODE_BGNLOOP && !s->end_loop) {
+                * instruction is used as the end of the live interval and
+                * the BGNLOOP instruction is used as the beginning. */
+               if (inst->U.I.Opcode == RC_OPCODE_BGNLOOP && s->EndLoop < 0) {
+                       s->BeginLoop = inst->IP;
                        int loops = 1;
                        struct rc_instruction * tmp;
                        for(tmp = inst->Next;
@@ -219,15 +228,17 @@ static void compute_live_intervals(struct radeon_compiler *c,
                                } else if (tmp->U.I.Opcode
                                                        == RC_OPCODE_ENDLOOP) {
                                        if(!--loops) {
-                                               s->end_loop = tmp->IP;
+                                               s->EndLoop = tmp->IP;
                                                break;
                                        }
                                }
                        }
                }
 
-               if (inst->IP == s->end_loop)
-                       s->end_loop = 0;
+               if (inst->IP == s->EndLoop) {
+                       s->EndLoop = -1;
+                       s->BeginLoop = -1;
+               }
 
                rc_for_all_reads_mask(inst, scan_callback, s);
                rc_for_all_writes_mask(inst, scan_callback, s);