[Tarantool-patches] [PATCH luajit 1/4] Fix math.min()/math.max() inconsistencies.

[Maxim Kokryashkin via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

From: Mike Pall <mike>

---
 src/lj_asm_arm.h   |  6 +++---
 src/lj_asm_arm64.h |  6 +++---
 src/lj_opt_fold.c  | 53 +++++++++++++++++-----------------------------
 src/lj_vmmath.c    |  4 ++--
 src/vm_arm.dasc    |  4 ++--
 src/vm_arm64.dasc  |  4 ++--
 src/vm_x64.dasc    |  2 +-
 src/vm_x86.dasc    |  2 +-
 8 files changed, 33 insertions(+), 48 deletions(-)

diff --git a/src/lj_asm_arm.h b/src/lj_asm_arm.h
index 4fd08b9e..84ab06c0 100644
--- a/src/lj_asm_arm.h
+++ b/src/lj_asm_arm.h
@@ -1664,8 +1664,8 @@ static void asm_min_max(ASMState *as, IRIns *ir, int cc, int fcc)
     asm_intmin_max(as, ir, cc);
 }
 
-#define asm_min(as, ir)		asm_min_max(as, ir, CC_GT, CC_HI)
-#define asm_max(as, ir)		asm_min_max(as, ir, CC_LT, CC_LO)
+#define asm_min(as, ir)		asm_min_max(as, ir, CC_GT, CC_PL)
+#define asm_max(as, ir)		asm_min_max(as, ir, CC_LT, CC_LE)
 
 /* -- Comparisons --------------------------------------------------------- */
 
@@ -1857,7 +1857,7 @@ static void asm_hiop(ASMState *as, IRIns *ir)
   } else if ((ir-1)->o == IR_MIN || (ir-1)->o == IR_MAX) {
     as->curins--;  /* Always skip the loword min/max. */
     if (uselo || usehi)
-      asm_sfpmin_max(as, ir-1, (ir-1)->o == IR_MIN ? CC_HI : CC_LO);
+      asm_sfpmin_max(as, ir-1, (ir-1)->o == IR_MIN ? CC_PL : CC_LE);
     return;
 #elif LJ_HASFFI
   } else if ((ir-1)->o == IR_CONV) {
diff --git a/src/lj_asm_arm64.h b/src/lj_asm_arm64.h
index a32ba2db..eb343b9a 100644
--- a/src/lj_asm_arm64.h
+++ b/src/lj_asm_arm64.h
@@ -1594,7 +1594,7 @@ static void asm_fpmin_max(ASMState *as, IRIns *ir, A64CC fcc)
   Reg dest = (ra_dest(as, ir, RSET_FPR) & 31);
   Reg right, left = ra_alloc2(as, ir, RSET_FPR);
   right = ((left >> 8) & 31); left &= 31;
-  emit_dnm(as, A64I_FCSELd | A64F_CC(fcc), dest, left, right);
+  emit_dnm(as, A64I_FCSELd | A64F_CC(fcc), dest, right, left);
   emit_nm(as, A64I_FCMPd, left, right);
 }
 
@@ -1606,8 +1606,8 @@ static void asm_min_max(ASMState *as, IRIns *ir, A64CC cc, A64CC fcc)
     asm_intmin_max(as, ir, cc);
 }
 
-#define asm_max(as, ir)		asm_min_max(as, ir, CC_GT, CC_HI)
-#define asm_min(as, ir)		asm_min_max(as, ir, CC_LT, CC_LO)
+#define asm_min(as, ir)		asm_min_max(as, ir, CC_LT, CC_PL)
+#define asm_max(as, ir)		asm_min_max(as, ir, CC_GT, CC_LE)
 
 /* -- Comparisons --------------------------------------------------------- */
 
diff --git a/src/lj_opt_fold.c b/src/lj_opt_fold.c
index 3c508062..29b760b4 100644
--- a/src/lj_opt_fold.c
+++ b/src/lj_opt_fold.c
@@ -1774,8 +1774,6 @@ LJFOLDF(reassoc_intarith_k64)
 #endif
 }
 
-LJFOLD(MIN MIN any)
-LJFOLD(MAX MAX any)
 LJFOLD(BAND BAND any)
 LJFOLD(BOR BOR any)
 LJFOLDF(reassoc_dup)
@@ -1785,6 +1783,15 @@ LJFOLDF(reassoc_dup)
   return NEXTFOLD;
 }
 
+LJFOLD(MIN MIN any)
+LJFOLD(MAX MAX any)
+LJFOLDF(reassoc_dup_minmax)
+{
+  if (fins->op2 == fleft->op2)
+    return LEFTFOLD;  /* (a o b) o b ==> a o b */
+  return NEXTFOLD;
+}
+
 LJFOLD(BXOR BXOR any)
 LJFOLDF(reassoc_bxor)
 {
@@ -1823,23 +1830,12 @@ LJFOLDF(reassoc_shift)
   return NEXTFOLD;
 }
 
-LJFOLD(MIN MIN KNUM)
-LJFOLD(MAX MAX KNUM)
 LJFOLD(MIN MIN KINT)
 LJFOLD(MAX MAX KINT)
 LJFOLDF(reassoc_minmax_k)
 {
   IRIns *irk = IR(fleft->op2);
-  if (irk->o == IR_KNUM) {
-    lua_Number a = ir_knum(irk)->n;
-    lua_Number y = lj_vm_foldarith(a, knumright, fins->o - IR_ADD);
-    if (a == y)  /* (x o k1) o k2 ==> x o k1, if (k1 o k2) == k1. */
-      return LEFTFOLD;
-    PHIBARRIER(fleft);
-    fins->op1 = fleft->op1;
-    fins->op2 = (IRRef1)lj_ir_knum(J, y);
-    return RETRYFOLD;  /* (x o k1) o k2 ==> x o (k1 o k2) */
-  } else if (irk->o == IR_KINT) {
+  if (irk->o == IR_KINT) {
     int32_t a = irk->i;
     int32_t y = kfold_intop(a, fright->i, fins->o);
     if (a == y)  /* (x o k1) o k2 ==> x o k1, if (k1 o k2) == k1. */
@@ -1852,24 +1848,6 @@ LJFOLDF(reassoc_minmax_k)
   return NEXTFOLD;
 }
 
-LJFOLD(MIN MAX any)
-LJFOLD(MAX MIN any)
-LJFOLDF(reassoc_minmax_left)
-{
-  if (fins->op2 == fleft->op1 || fins->op2 == fleft->op2)
-    return RIGHTFOLD;  /* (b o1 a) o2 b ==> b; (a o1 b) o2 b ==> b */
-  return NEXTFOLD;
-}
-
-LJFOLD(MIN any MAX)
-LJFOLD(MAX any MIN)
-LJFOLDF(reassoc_minmax_right)
-{
-  if (fins->op1 == fright->op1 || fins->op1 == fright->op2)
-    return LEFTFOLD;  /* a o2 (a o1 b) ==> a; a o2 (b o1 a) ==> a */
-  return NEXTFOLD;
-}
-
 /* -- Array bounds check elimination -------------------------------------- */
 
 /* Eliminate ABC across PHIs to handle t[i-1] forwarding case.
@@ -1995,8 +1973,6 @@ LJFOLDF(comm_comp)
 
 LJFOLD(BAND any any)
 LJFOLD(BOR any any)
-LJFOLD(MIN any any)
-LJFOLD(MAX any any)
 LJFOLDF(comm_dup)
 {
   if (fins->op1 == fins->op2)  /* x o x ==> x */
@@ -2004,6 +1980,15 @@ LJFOLDF(comm_dup)
   return fold_comm_swap(J);
 }
 
+LJFOLD(MIN any any)
+LJFOLD(MAX any any)
+LJFOLDF(comm_dup_minmax)
+{
+  if (fins->op1 == fins->op2)  /* x o x ==> x */
+    return LEFTFOLD;
+  return NEXTFOLD;
+}
+
 LJFOLD(BXOR any any)
 LJFOLDF(comm_bxor)
 {
diff --git a/src/lj_vmmath.c b/src/lj_vmmath.c
index b231d3e8..08ccf467 100644
--- a/src/lj_vmmath.c
+++ b/src/lj_vmmath.c
@@ -50,8 +50,8 @@ double lj_vm_foldarith(double x, double y, int op)
 #if LJ_HASJIT
   case IR_ATAN2 - IR_ADD: return atan2(x, y); break;
   case IR_LDEXP - IR_ADD: return ldexp(x, (int)y); break;
-  case IR_MIN - IR_ADD: return x > y ? y : x; break;
-  case IR_MAX - IR_ADD: return x < y ? y : x; break;
+  case IR_MIN - IR_ADD: return x < y ? x : y; break;
+  case IR_MAX - IR_ADD: return x > y ? x : y; break;
 #endif
   default: return x;
   }
diff --git a/src/vm_arm.dasc b/src/vm_arm.dasc
index 21f7fecb..6b511347 100644
--- a/src/vm_arm.dasc
+++ b/src/vm_arm.dasc
@@ -1718,8 +1718,8 @@ static void build_subroutines(BuildCtx *ctx)
   |.endif
   |.endmacro
   |
-  |  math_minmax math_min, gt, hi
-  |  math_minmax math_max, lt, lo
+  |  math_minmax math_min, gt, pl
+  |  math_minmax math_max, lt, le
   |
   |//-- String library -----------------------------------------------------
   |
diff --git a/src/vm_arm64.dasc b/src/vm_arm64.dasc
index ddcf0f11..17f472fb 100644
--- a/src/vm_arm64.dasc
+++ b/src/vm_arm64.dasc
@@ -1489,8 +1489,8 @@ static void build_subroutines(BuildCtx *ctx)
   |  b <6
   |.endmacro
   |
-  |  math_minmax math_min, gt, hi
-  |  math_minmax math_max, lt, lo
+  |  math_minmax math_min, gt, pl
+  |  math_minmax math_max, lt, le
   |
   |//-- String library -----------------------------------------------------
   |
diff --git a/src/vm_x64.dasc b/src/vm_x64.dasc
index 974047d3..cbf5fb9b 100644
--- a/src/vm_x64.dasc
+++ b/src/vm_x64.dasc
@@ -1874,7 +1874,7 @@ static void build_subroutines(BuildCtx *ctx)
   |  jmp ->fff_res
   |
   |.macro math_minmax, name, cmovop, sseop
-  |  .ffunc name
+  |  .ffunc_1 name
   |  mov RAd, 2
   |.if DUALNUM
   |  mov RB, [BASE]
diff --git a/src/vm_x86.dasc b/src/vm_x86.dasc
index ab8e6f27..b839eff0 100644
--- a/src/vm_x86.dasc
+++ b/src/vm_x86.dasc
@@ -2292,7 +2292,7 @@ static void build_subroutines(BuildCtx *ctx)
   |  xorps xmm4, xmm4; jmp <1			// Return +-Inf and +-0.
   |
   |.macro math_minmax, name, cmovop, sseop
-  |  .ffunc name
+  |  .ffunc_1 name
   |  mov RA, 2
   |  cmp dword [BASE+4], LJ_TISNUM
   |.if DUALNUM
-- 
2.33.0