Revert "tcg: Do not kill globals at conditional branches"

This reverts commit b4cb76e6208cf6b5bb39404c6d44a6514eb6842a.

3 files changed, 6 insertions, 60 deletions

diff --git a/include/tcg/tcg-opc.h b/include/tcg/tcg-opc.h
index 67092e82c6..e3929b80d2 100644
--- a/include/tcg/tcg-opc.h
+++ b/include/tcg/tcg-opc.h
@@ -81,7 +81,7 @@ DEF(extract_i32, 1, 1, 2, IMPL(TCG_TARGET_HAS_extract_i32))
 DEF(sextract_i32, 1, 1, 2, IMPL(TCG_TARGET_HAS_sextract_i32))
 DEF(extract2_i32, 1, 2, 1, IMPL(TCG_TARGET_HAS_extract2_i32))
 
-DEF(brcond_i32, 0, 2, 2, TCG_OPF_BB_END | TCG_OPF_COND_BRANCH)
+DEF(brcond_i32, 0, 2, 2, TCG_OPF_BB_END)
 
 DEF(add2_i32, 2, 4, 0, IMPL(TCG_TARGET_HAS_add2_i32))
 DEF(sub2_i32, 2, 4, 0, IMPL(TCG_TARGET_HAS_sub2_i32))
@@ -89,8 +89,7 @@ DEF(mulu2_i32, 2, 2, 0, IMPL(TCG_TARGET_HAS_mulu2_i32))
 DEF(muls2_i32, 2, 2, 0, IMPL(TCG_TARGET_HAS_muls2_i32))
 DEF(muluh_i32, 1, 2, 0, IMPL(TCG_TARGET_HAS_muluh_i32))
 DEF(mulsh_i32, 1, 2, 0, IMPL(TCG_TARGET_HAS_mulsh_i32))
-DEF(brcond2_i32, 0, 4, 2,
-    TCG_OPF_BB_END | TCG_OPF_COND_BRANCH | IMPL(TCG_TARGET_REG_BITS == 32))
+DEF(brcond2_i32, 0, 4, 2, TCG_OPF_BB_END | IMPL(TCG_TARGET_REG_BITS == 32))
 DEF(setcond2_i32, 1, 4, 1, IMPL(TCG_TARGET_REG_BITS == 32))
 
 DEF(ext8s_i32, 1, 1, 0, IMPL(TCG_TARGET_HAS_ext8s_i32))
@@ -160,7 +159,7 @@ DEF(extrh_i64_i32, 1, 1, 0,
     IMPL(TCG_TARGET_HAS_extrh_i64_i32)
     | (TCG_TARGET_REG_BITS == 32 ? TCG_OPF_NOT_PRESENT : 0))
 
-DEF(brcond_i64, 0, 2, 2, TCG_OPF_BB_END | TCG_OPF_COND_BRANCH | IMPL64)
+DEF(brcond_i64, 0, 2, 2, TCG_OPF_BB_END | IMPL64)
 DEF(ext8s_i64, 1, 1, 0, IMPL64 | IMPL(TCG_TARGET_HAS_ext8s_i64))
 DEF(ext16s_i64, 1, 1, 0, IMPL64 | IMPL(TCG_TARGET_HAS_ext16s_i64))
 DEF(ext32s_i64, 1, 1, 0, IMPL64 | IMPL(TCG_TARGET_HAS_ext32s_i64))
diff --git a/include/tcg/tcg.h b/include/tcg/tcg.h
index 8ff9dad4ef..8804a8c4a2 100644
--- a/include/tcg/tcg.h
+++ b/include/tcg/tcg.h
@@ -990,7 +990,7 @@ typedef struct TCGArgConstraint {
 
 #define TCG_MAX_OP_ARGS 16
 
-/* Bits for TCGOpDef->flags, 8 bits available, all used.  */
+/* Bits for TCGOpDef->flags, 8 bits available.  */
 enum {
     /* Instruction exits the translation block.  */
     TCG_OPF_BB_EXIT      = 0x01,
@@ -1008,8 +1008,6 @@ enum {
     TCG_OPF_NOT_PRESENT  = 0x20,
     /* Instruction operands are vectors.  */
     TCG_OPF_VECTOR       = 0x40,
-    /* Instruction is a conditional branch. */
-    TCG_OPF_COND_BRANCH  = 0x80
 };
 
 typedef struct TCGOpDef {
diff --git a/tcg/tcg.c b/tcg/tcg.c
index f49f1a7f35..a8c28440e2 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -2519,28 +2519,6 @@ static void la_global_sync(TCGContext *s, int ng)
     }
 }
 
-/*
- * liveness analysis: conditional branch: all temps are dead,
- * globals and local temps should be synced.
- */
-static void la_bb_sync(TCGContext *s, int ng, int nt)
-{
-    la_global_sync(s, ng);
-
-    for (int i = ng; i < nt; ++i) {
-        if (s->temps[i].temp_local) {
-            int state = s->temps[i].state;
-            s->temps[i].state = state | TS_MEM;
-            if (state != TS_DEAD) {
-                continue;
-            }
-        } else {
-            s->temps[i].state = TS_DEAD;
-        }
-        la_reset_pref(&s->temps[i]);
-    }
-}
-
 /* liveness analysis: sync globals back to memory and kill.  */
 static void la_global_kill(TCGContext *s, int ng)
 {
@@ -2817,8 +2795,6 @@ static void liveness_pass_1(TCGContext *s)
             /* If end of basic block, update.  */
             if (def->flags & TCG_OPF_BB_EXIT) {
                 la_func_end(s, nb_globals, nb_temps);
-            } else if (def->flags & TCG_OPF_COND_BRANCH) {
-                la_bb_sync(s, nb_globals, nb_temps);
             } else if (def->flags & TCG_OPF_BB_END) {
                 la_bb_end(s, nb_globals, nb_temps);
             } else if (def->flags & TCG_OPF_SIDE_EFFECTS) {
@@ -2931,10 +2907,7 @@ static bool liveness_pass_2(TCGContext *s)
             nb_oargs = def->nb_oargs;
 
             /* Set flags similar to how calls require.  */
-            if (def->flags & TCG_OPF_COND_BRANCH) {
-                /* Like reading globals: sync_globals */
-                call_flags = TCG_CALL_NO_WRITE_GLOBALS;
-            } else if (def->flags & TCG_OPF_BB_END) {
+            if (def->flags & TCG_OPF_BB_END) {
                 /* Like writing globals: save_globals */
                 call_flags = 0;
             } else if (def->flags & TCG_OPF_SIDE_EFFECTS) {
@@ -3407,28 +3380,6 @@ static void tcg_reg_alloc_bb_end(TCGContext *s, TCGRegSet allocated_regs)
 }
 
 /*
- * At a conditional branch, we assume all temporaries are dead and
- * all globals and local temps are synced to their location.
- */
-static void tcg_reg_alloc_cbranch(TCGContext *s, TCGRegSet allocated_regs)
-{
-    sync_globals(s, allocated_regs);
-
-    for (int i = s->nb_globals; i < s->nb_temps; i++) {
-        TCGTemp *ts = &s->temps[i];
-        /*
-         * The liveness analysis already ensures that temps are dead.
-         * Keep tcg_debug_asserts for safety.
-         */
-        if (ts->temp_local) {
-            tcg_debug_assert(ts->val_type != TEMP_VAL_REG || ts->mem_coherent);
-        } else {
-            tcg_debug_assert(ts->val_type == TEMP_VAL_DEAD);
-        }
-    }
-}
-
-/*
  * Specialized code generation for INDEX_op_movi_*.
  */
 static void tcg_reg_alloc_do_movi(TCGContext *s, TCGTemp *ots,
@@ -3779,9 +3730,7 @@ static void tcg_reg_alloc_op(TCGContext *s, const TCGOp *op)
         }
     }
 
-    if (def->flags & TCG_OPF_COND_BRANCH) {
-        tcg_reg_alloc_cbranch(s, i_allocated_regs);
-    } else if (def->flags & TCG_OPF_BB_END) {
+    if (def->flags & TCG_OPF_BB_END) {
         tcg_reg_alloc_bb_end(s, i_allocated_regs);
     } else {
         if (def->flags & TCG_OPF_CALL_CLOBBER) {