On Mon, Jul 13, 2026 at 5:06 PM Richard Biener <[email protected]> wrote:
>
> On Sat, 11 Jul 2026, H.J. Lu wrote:
>
> > commit e754b70fe5470b975d31887fa5647f1c92d6522d
> > Author: H.J. Lu <[email protected]>
> > Date:   Tue Apr 7 23:16:38 2026 +0800
> >
> >     x86: Rewrite ix86_find_max_used_stack_alignment
> >
> > doesn't handle
> >
> > (insn 13 12 14 2 (set (reg:DI 0 ax [orig:112 _35 ] [112])
> >         (sign_extend:DI (mem/c:SI (symbol_ref:DI
> > ("vpx_quantize_b_avx_index") [flags 0x2] <var_decl 0x7fffe941f000
> > vpx_quantize_b_avx_index>) [2 vpx_quantize_b_avx_index+0 S4 A32])))
> > "z.c":14:56 188 {*extendsidi2_rex64}
> >      (nil))
> > ...
> > (insn 21 20 35 4 (set (mem:V4DI (reg/f:DI 0 ax [orig:104 _38 ] [104])
> > [1 MEM[(__m256i *)_38]+0 S32 A256])
> >         (reg:V4DI 20 xmm0 [116])) "z.c":5:59 2459 {movv4di_internal}
> >      (nil))
> >
> > correctly since it assumes that
> >
> > (mem:V4DI (reg/f:DI 0 ax [orig:104 _38 ] [104]) [1 MEM[(__m256i
> > *)_38]+0 S32 A256])
> >
> > is on stack.
>
> What do you mean by "correctly"?  It is conservatively correct
> to assume  "on stack".  It seems we still assert that somehow
> early analysis (during expand) matches up with late IL analysis
> (wherever) in "optimality"?  We cannot do such thing.  What
> is (should be) guaranteed is that if at RTL expansion time
> we concluded something is _not_ on stack then we should not
> be able to late _prove_ it is on stack - but all we can do
> is perform conservative assessment, meaning we have to error
> on the "on stack" side.
>
> If we can _prove_ nothing on the stack has alignment > X then
> we can possibly late lower required stack alignment.  But we
> shouldn't assert that we compute a late required alignment
> of <= the original alignment, if the IL degraded we can end
> up with > original alignment, which we can disregard, doing
> nothing, since the initial computation has to be conservative
> already.
>
> Instead of again adding x86 specific "points-to hacks", please
> make sure we do not have such bogus assertions and if needed
> for optimization, improve RTL points-to analysis.
>
> Richard.
>

I'd like to revert

commit e754b70fe5470b975d31887fa5647f1c92d6522d
Author:     H.J. Lu <[email protected]>
AuthorDate: Tue Apr 7 23:16:38 2026 +0800
Commit:     H.J. Lu <[email protected]>
CommitDate: Mon Jul 6 16:11:45 2026 +0800

    x86: Rewrite ix86_find_max_used_stack_alignment

and add 2 tests.  We can revisit it later.

-- 
H.J.
---
Revert

commit e754b70fe5470b975d31887fa5647f1c92d6522d
Author:     H.J. Lu <[email protected]>
AuthorDate: Tue Apr 7 23:16:38 2026 +0800
Commit:     H.J. Lu <[email protected]>
CommitDate: Mon Jul 6 16:11:45 2026 +0800

    x86: Rewrite ix86_find_max_used_stack_alignment

to fix PR target/126202.

gcc/

PR target/126202
* alias.cc (static_reg_base_value): Revert commit e754b70fe54.
(find_base_term): Likewise.
* alias.h (find_base_term): Likewise.
* function.cc (thread_prologue_and_epilogue_insns): Likewise.
* rtl.h (static_reg_base_value): Likewise.
* config/i386/i386.cc (stack_access_data): Likewise.
(ix86_find_all_reg_uses_1): Likewise.
(ix86_find_all_reg_uses): Likewise.
(ix86_access_stack_p): Likewise.
(ix86_need_alignment_p_2): Likewise.
(ix86_need_alignment_p_1): Likewise.
(ix86_need_alignment_p): Likewise.
(ix86_update_stack_alignment): Likewise.
(ix86_find_max_used_stack_alignment): Likewise.
(ix86_update_stack_alignment_2): Removed.
(ix86_update_stack_alignment_1): Likewise.

gcc/testsuite/

PR target/126202
* g++.target/i386/pr126202-1.C: New test.
* gcc.target/i386/pr126202-1.c: Likewise.
From 93d9fe82977cde09516a991e60fe0944ece31b8d Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <[email protected]>
Date: Tue, 14 Jul 2026 05:25:45 +0800
Subject: [PATCH] Revert "x86: Rewrite ix86_find_max_used_stack_alignment"

Revert

commit e754b70fe5470b975d31887fa5647f1c92d6522d
Author:     H.J. Lu <[email protected]>
AuthorDate: Tue Apr 7 23:16:38 2026 +0800
Commit:     H.J. Lu <[email protected]>
CommitDate: Mon Jul 6 16:11:45 2026 +0800

    x86: Rewrite ix86_find_max_used_stack_alignment

to fix PR target/126202.

gcc/

	PR target/126202
	* alias.cc (static_reg_base_value): Revert commit e754b70fe54.
	(find_base_term): Likewise.
	* alias.h (find_base_term): Likewise.
	* function.cc (thread_prologue_and_epilogue_insns): Likewise.
	* rtl.h (static_reg_base_value): Likewise.
	* config/i386/i386.cc (stack_access_data): Likewise.
	(ix86_find_all_reg_uses_1): Likewise.
	(ix86_find_all_reg_uses): Likewise.
	(ix86_access_stack_p): Likewise.
	(ix86_need_alignment_p_2): Likewise.
	(ix86_need_alignment_p_1): Likewise.
	(ix86_need_alignment_p): Likewise.
	(ix86_update_stack_alignment): Likewise.
	(ix86_find_max_used_stack_alignment): Likewise.
	(ix86_update_stack_alignment_2): Removed.
	(ix86_update_stack_alignment_1): Likewise.

gcc/testsuite/

	PR target/126202
	* g++.target/i386/pr126202-1.C: New test.
	* gcc.target/i386/pr126202-1.c: Likewise.

Signed-off-by: H.J. Lu <[email protected]>
---
 gcc/alias.cc                               |   5 +-
 gcc/alias.h                                |   1 -
 gcc/config/i386/i386.cc                    | 399 ++++++++++++++-------
 gcc/function.cc                            |   6 -
 gcc/rtl.h                                  |   2 -
 gcc/testsuite/g++.target/i386/pr126202-1.C |  71 ++++
 gcc/testsuite/gcc.target/i386/pr126202-1.c |  29 ++
 7 files changed, 381 insertions(+), 132 deletions(-)
 create mode 100644 gcc/testsuite/g++.target/i386/pr126202-1.C
 create mode 100644 gcc/testsuite/gcc.target/i386/pr126202-1.c

diff --git a/gcc/alias.cc b/gcc/alias.cc
index 3048a1e2354..abba2dd9f82 100644
--- a/gcc/alias.cc
+++ b/gcc/alias.cc
@@ -232,6 +232,9 @@ static GTY((deletable)) vec<rtx, va_gc> *old_reg_base_value;
 #define UNIQUE_BASE_VALUE_FP	-3
 #define UNIQUE_BASE_VALUE_HFP	-4
 
+#define static_reg_base_value \
+  (this_target_rtl->x_static_reg_base_value)
+
 #define REG_BASE_VALUE(X)					\
   (REGNO (X) < vec_safe_length (reg_base_value)			\
    ? (*reg_base_value)[REGNO (X)] : 0)
@@ -2062,7 +2065,7 @@ find_base_term (rtx x, vec<std::pair<cselib_val *,
 /* Wrapper around the worker above which removes locs from visited VALUEs
    to avoid visiting them multiple times.  We unwind that changes here.  */
 
-rtx
+static rtx
 find_base_term (rtx x)
 {
   auto_vec<std::pair<cselib_val *, struct elt_loc_list *>, 32> visited_vals;
diff --git a/gcc/alias.h b/gcc/alias.h
index 1e43111f580..4bd49bb0fa4 100644
--- a/gcc/alias.h
+++ b/gcc/alias.h
@@ -42,7 +42,6 @@ int compare_base_decls (tree, tree);
 bool refs_same_for_tbaa_p (tree, tree);
 bool mems_same_for_tbaa_p (rtx, rtx);
 bool view_converted_memref_p (tree);
-extern rtx find_base_term (rtx);
 
 /* This alias set can be used to force a memory to conflict with all
    other memories, creating a barrier across which no memory reference
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 64fe3231164..043faf80309 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -8615,135 +8615,221 @@ output_probe_stack_range (rtx reg, rtx end)
   return "";
 }
 
-/* Update the maximum stack slot alignment from memory alignment if
-   OP is stack memory.  */
+/* Data passed to ix86_update_stack_alignment.  */
+struct stack_access_data
+{
+  /* The stack access register.  */
+  const_rtx reg;
+  /* Pointer to stack alignment.  */
+  unsigned int *stack_alignment;
+};
+
+/* Return true if OP references an argument passed on stack.  */
+
+static bool
+ix86_argument_passed_on_stack_p (const_rtx op)
+{
+  tree mem_expr = MEM_EXPR (op);
+  if (mem_expr)
+    {
+      tree var = get_base_address (mem_expr);
+      return TREE_CODE (var) == PARM_DECL;
+    }
+  return false;
+}
+
+/* Update the maximum stack slot alignment from memory alignment in PAT.  */
 
 static void
-ix86_update_stack_alignment_2 (const_rtx op, unsigned int &alignment)
+ix86_update_stack_alignment (rtx, const_rtx pat, void *data)
 {
-  unsigned int mem_align = MEM_ALIGN (op);
-  if (mem_align <= alignment)
-    return;
+  /* This insn may reference stack slot.  Update the maximum stack slot
+     alignment if the memory is referenced by the stack access register. */
+  stack_access_data *p = (stack_access_data *) data;
+
+  subrtx_iterator::array_type array;
+  FOR_EACH_SUBRTX (iter, array, pat, ALL)
+    {
+      auto op = *iter;
+      if (MEM_P (op))
+	{
+	  /* NB: Ignore arguments passed on stack since caller is
+	     responsible to align the outgoing stack for arguments
+	     passed on stack.  */
+	  if (reg_mentioned_p (p->reg, XEXP (op, 0))
+	      && !ix86_argument_passed_on_stack_p (op))
+	    {
+	      unsigned int alignment = MEM_ALIGN (op);
+
+	      if (alignment > *p->stack_alignment)
+		*p->stack_alignment = alignment;
+	      break;
+	    }
+	  else
+	    iter.skip_subrtxes ();
+	}
+    }
+}
 
-  /* Skip if OP is a memory operand with CONST_INT in
+/* Helper function for ix86_find_all_reg_uses.  */
 
-     (set (mem/v:SI (const_int 0 [0]) [14 MEM[(int *)0B]+0 S4 A256])
-	  (const_int 0 [0]))
+static void
+ix86_find_all_reg_uses_1 (HARD_REG_SET &regset,
+			  rtx set, unsigned int regno,
+			  auto_bitmap &worklist)
+{
+  rtx dest = SET_DEST (set);
 
-     or SYMBOLIC_CONST in
+  if (!REG_P (dest))
+    return;
 
-     (set (reg:SI 0 ax [orig:118 _2 ] [118])
-	  (sign_extend:SI (mem/c:QI (symbol_ref:DI ("c") [flags 0x2] <var_decl 0x7fffe960de40 c>) [0 c+0 S1 A8])))
-   */
-  rtx x = XEXP (op, 0);
-  if (CONST_INT_P (x) || SYMBOLIC_CONST (x))
+  /* Reject non-Pmode modes.  */
+  if (GET_MODE (dest) != Pmode)
+    return;
+
+  unsigned int dst_regno = REGNO (dest);
+
+  if (TEST_HARD_REG_BIT (regset, dst_regno))
     return;
 
-  /* Skip if OP is function result on stack in
+  const_rtx src = SET_SRC (set);
 
-     (set (mem/c:TI (reg/f:SI 0 ax [orig:99 .result_ptr ] [99]) [2 <retval>+0 S16 A128])
-	  (reg:TI 20 xmm0 [orig:100 x ] [100]))
-  */
-  tree result_decl = DECL_RESULT (current_function_decl);
-  if (result_decl && DECL_RTL_SET_P (result_decl))
+  subrtx_iterator::array_type array;
+  FOR_EACH_SUBRTX (iter, array, src, ALL)
     {
-      rtx result_rtl = DECL_RTL (result_decl);
-      if (MEM_P (result_rtl) && XEXP (result_rtl, 0) == x)
-	return;
-    }
+      auto op = *iter;
 
-  /* All stack is in the generic address space.  Skip
+      if (MEM_P (op))
+	iter.skip_subrtxes ();
 
-     (mem:DI (reg:DI 2 cx [103]) [4 MEM[(<address-space-1> __int128 *)0B]+0 S8 A128 AS1])
+      if (REG_P (op) && REGNO (op) == regno)
+	{
+	  /* Add this register to register set.  */
+	  add_to_hard_reg_set (&regset, Pmode, dst_regno);
+	  bitmap_set_bit (worklist, dst_regno);
+	  break;
+	}
+    }
+}
 
-     from from gcc.target/i386/apx-ndd-seg-1.c.  */
-  if (MEM_ADDR_SPACE (op) != ADDR_SPACE_GENERIC)
-    return;
+/* Find all registers defined with register REGNO.  */
 
-  rtx base = find_base_term (x);
-  if (base)
+static void
+ix86_find_all_reg_uses (HARD_REG_SET &regset,
+			unsigned int regno, auto_bitmap &worklist)
+{
+  for (df_ref ref = DF_REG_USE_CHAIN (regno);
+       ref != NULL;
+       ref = DF_REF_NEXT_REG (ref))
     {
-      /* Update ALIGNMENT if RTL points-to says OP accesses stack.  */
-      if (base == static_reg_base_value[STACK_POINTER_REGNUM]
-	  || base == static_reg_base_value[FRAME_POINTER_REGNUM])
-	alignment = mem_align;
-      return;
-    }
+      if (DF_REF_IS_ARTIFICIAL (ref))
+	continue;
 
-  /* RTL points-to isn't available.  */
-  bool ok;
-  struct ix86_address parts;
-  ok = ix86_decompose_address (x, &parts);
-  gcc_assert (ok);
+      rtx_insn *insn = DF_REF_INSN (ref);
 
-  /* Skip if displacement is SYMBOLIC_CONST in
+      if (!NONJUMP_INSN_P (insn))
+	continue;
 
-     (set (mem:V16QI (plus:SI (reg:SI 2 cx [orig:105 niters_vector_mult_vf.6 ] [105])
-			      (symbol_ref:SI ("perm") [flags 0x2] <var_decl 0x7fffe9613130 perm>)) [0 MEM <vector(16) char> [(char *)vectp_perm.21_69]+0 S16 A256])
-	  (reg:V16QI 20 xmm0 [orig:179 vect__13.18_68 ] [179]))
+      unsigned int ref_regno = DF_REF_REGNO (ref);
 
-     from gcc.target/i386/pr109780-1.c.  */
-  if (parts.disp && SYMBOLIC_CONST (parts.disp))
-    return;
+      rtx set = single_set (insn);
+      if (set)
+	{
+	  ix86_find_all_reg_uses_1 (regset, set,
+				    ref_regno, worklist);
+	  continue;
+	}
 
-  tree mem_expr = MEM_EXPR (op);
-  if (mem_expr)
-    {
-      tree var = get_base_address (mem_expr);
+      rtx pat = PATTERN (insn);
+      if (GET_CODE (pat) != PARALLEL)
+	continue;
 
-      if (TREE_CODE (var) == MEM_REF
-	  || TREE_CODE (var) == TARGET_MEM_REF)
+      for (int i = 0; i < XVECLEN (pat, 0); i++)
 	{
-	   tree ptr = TREE_OPERAND (var, 0);
-	   if (TREE_CODE (ptr) == BIT_AND_EXPR)
-	     ptr = TREE_OPERAND (ptr, 0);
+	  rtx exp = XVECEXP (pat, 0, i);
 
-	   /* Skip if OP is a memory operand of non-local reference in
+	  if (GET_CODE (exp) == SET)
+	    ix86_find_all_reg_uses_1 (regset, exp,
+				      ref_regno, worklist);
+	}
+    }
+}
+
+/* Return true if the hard register REGNO used for a stack access is
+   defined in a basic block that dominates the block where it is used.  */
 
-	      (set (mem:V4DI (reg:DI 0 ax [orig:112 ivtmp.23 ] [112]) [1 MEM <vector(4) unsigned long> [(_BitInt(2048) *)_34]+0 S32 A256])
-		   (reg:V4DI 20 xmm0 [117]))
+static bool
+ix86_access_stack_p (unsigned int regno, basic_block bb,
+		     HARD_REG_SET &set_up_by_prologue,
+		     HARD_REG_SET &prologue_used,
+		     auto_bitmap reg_dominate_bbs_known[],
+		     auto_bitmap reg_dominate_bbs[])
+{
+  if (bitmap_bit_p (reg_dominate_bbs_known[regno], bb->index))
+    return bitmap_bit_p (reg_dominate_bbs[regno], bb->index);
+
+  bitmap_set_bit (reg_dominate_bbs_known[regno], bb->index);
+
+  /* Get all BBs which set REGNO and dominate the current BB from all
+     DEFs of REGNO.  */
+  for (df_ref def = DF_REG_DEF_CHAIN (regno);
+       def;
+       def = DF_REF_NEXT_REG (def))
+    if (!DF_REF_IS_ARTIFICIAL (def)
+	&& !DF_REF_FLAGS_IS_SET (def, DF_REF_MAY_CLOBBER)
+	&& !DF_REF_FLAGS_IS_SET (def, DF_REF_MUST_CLOBBER))
+      {
+	basic_block set_bb = DF_REF_BB (def);
+	if (dominated_by_p (CDI_DOMINATORS, bb, set_bb))
+	  {
+	    rtx_insn *insn = DF_REF_INSN (def);
+	    /* Return true if INSN requires stack.  */
+	    if (requires_stack_frame_p (insn, prologue_used,
+					set_up_by_prologue))
+	      {
+		bitmap_set_bit (reg_dominate_bbs[regno], bb->index);
+		return true;
+	      }
+	  }
+      }
 
-	      from gcc.target/i386/pr124098.c.  */
-	   if (!ptr_deref_may_alias_auto_p (ptr)
-	       /* An access based on an incoming pointer cannot point to
-		  local stack as in
+  /* When we get here, REGNO used in the current BB doesn't access
+     stack.  */
+  return false;
+}
 
-		  (set (reg:V2DI 20 xmm0 [orig:103 MEM[(const __m128i * {ref-all})s_1(D) & 4294967280B] ] [103])
-		       (mem:V2DI (reg:SI 0 ax [102]) [0 MEM[(const __m128i * {ref-all})s_1(D) & 4294967280B]+0 S16 A128]))
+/* Return true if OP isn't a memory operand with SYMBOLIC_CONST and
+   needs alignment > ALIGNMENT.  */
 
-		  from gcc.target/i386/pr53907.  */
-	       || (TREE_CODE (ptr) == SSA_NAME
-		   && SSA_NAME_IS_DEFAULT_DEF (ptr)
-		   && TREE_CODE (SSA_NAME_VAR (ptr)) == PARM_DECL))
-	     return;
-	}
-      /* Skip if OP isn't a local stack variable in
+static bool
+ix86_need_alignment_p_2 (const_rtx op, unsigned int alignment)
+{
+  bool need_alignment = MEM_ALIGN (op) > alignment;
+  tree mem_expr = MEM_EXPR (op);
+  if (!mem_expr)
+    return need_alignment;
 
-	 (set (mem/c:DI (plus:DI (reg/f:DI 1 dx [157])
-				 (reg:DI 0 ax [98])) [2 __gcov8.foo.strub.0[0]+0 S8 A256])
-	      (ior:DI (mem/c:DI (plus:DI (reg/f:DI 1 dx [157])
-				(reg:DI 0 ax [98])) [2 __gcov8.foo.strub.0[0]+0 S8 A256])
-		      (const_int 1 [0x1])))
+  tree var = get_base_address (mem_expr);
+  if (!VAR_P (var) || !DECL_RTL_SET_P (var))
+    return need_alignment;
 
-	 from gcc.target/i386/pr123210.c.  */
-      else if (VAR_P (var)
-	       && !auto_var_in_fn_p (var, current_function_decl))
-	return;
-    }
+  rtx x = DECL_RTL (var);
+  if (!MEM_P (x))
+    return need_alignment;
 
-  alignment = mem_align;
+  x = XEXP (x, 0);
+  return !SYMBOLIC_CONST (x) && need_alignment;
 }
 
-/* Update the maximum stack slot alignment from memory alignment if
-   SET references stack memory.  */
+/* Return true if SET needs alignment > ALIGNMENT.  */
 
-static void
-ix86_update_stack_alignment_1 (rtx set, unsigned int &alignment)
+static bool
+ix86_need_alignment_p_1 (rtx set, unsigned int alignment)
 {
   rtx dest = SET_DEST (set);
 
   if (MEM_P (dest))
-    return ix86_update_stack_alignment_2 (dest, alignment);
+    return ix86_need_alignment_p_2 (dest, alignment);
 
   const_rtx src = SET_SRC (set);
 
@@ -8753,31 +8839,35 @@ ix86_update_stack_alignment_1 (rtx set, unsigned int &alignment)
       auto op = *iter;
 
       if (MEM_P (op))
-	return ix86_update_stack_alignment_2 (op, alignment);
+	return ix86_need_alignment_p_2 (op, alignment);
     }
+
+  return false;
 }
 
-/* Update the maximum stack slot alignment from memory alignment if
-   INSN references stack memory.  */
+/* Return true if INSN needs alignment > ALIGNMENT.  */
 
-static void
-ix86_update_stack_alignment (rtx_insn *insn, unsigned int &alignment)
+static bool
+ix86_need_alignment_p (rtx_insn *insn, unsigned int alignment)
 {
   rtx set = single_set (insn);
   if (set)
-    return ix86_update_stack_alignment_1 (set, alignment);
+    return ix86_need_alignment_p_1 (set, alignment);
 
   rtx pat = PATTERN (insn);
   if (GET_CODE (pat) != PARALLEL)
-    return;
+    return false;
 
   for (int i = 0; i < XVECLEN (pat, 0); i++)
     {
       rtx exp = XVECEXP (pat, 0, i);
 
-      if (GET_CODE (exp) == SET)
-	ix86_update_stack_alignment_1 (exp, alignment);
+      if (GET_CODE (exp) == SET
+	  && ix86_need_alignment_p_1 (exp, alignment))
+	return true;
     }
+
+  return false;
 }
 
 /* Set stack_frame_required to false if stack frame isn't required.
@@ -8798,38 +8888,103 @@ ix86_find_max_used_stack_alignment (unsigned int &stack_alignment,
   add_to_hard_reg_set (&set_up_by_prologue, Pmode,
 		       HARD_FRAME_POINTER_REGNUM);
 
-  cfun->machine->stack_frame_required = false;
-
-  /* The preferred stack alignment is the minimum stack alignment.  */
-  if (check_stack_slot
-      && stack_alignment > crtl->preferred_stack_boundary)
-    stack_alignment = crtl->preferred_stack_boundary;
+  bool require_stack_frame = false;
 
   FOR_EACH_BB_FN (bb, cfun)
     {
       rtx_insn *insn;
       FOR_BB_INSNS (bb, insn)
-	if (NONDEBUG_INSN_P (insn))
+	if (NONDEBUG_INSN_P (insn)
+	    && requires_stack_frame_p (insn, prologue_used,
+				       set_up_by_prologue))
 	  {
-	    if (!cfun->machine->stack_frame_required
-		&& requires_stack_frame_p (insn, prologue_used,
-					   set_up_by_prologue))
-	      {
-		/* Set stack_frame_required before calling
-		   ix86_update_stack_alignment.  */
-		cfun->machine->stack_frame_required = true;
+	    require_stack_frame = true;
+	    break;
+	  }
+    }
 
-		/* Stop if we don't need to check stack slot.  */
-		if (!check_stack_slot)
-		  break;
-	      }
+  cfun->machine->stack_frame_required = require_stack_frame;
 
-	    if (!check_stack_slot || !NONJUMP_INSN_P (insn))
-	      continue;
+  /* Stop if we don't need to check stack slot.  */
+  if (!check_stack_slot)
+    return;
 
-	    ix86_update_stack_alignment (insn, stack_alignment);
-	  }
+  /* The preferred stack alignment is the minimum stack alignment.  */
+  if (stack_alignment > crtl->preferred_stack_boundary)
+    stack_alignment = crtl->preferred_stack_boundary;
+
+  HARD_REG_SET stack_slot_access;
+  CLEAR_HARD_REG_SET (stack_slot_access);
+
+  /* Stack slot can be accessed by stack pointer, frame pointer or
+     registers defined by stack pointer or frame pointer.  */
+  auto_bitmap worklist;
+
+  add_to_hard_reg_set (&stack_slot_access, Pmode, STACK_POINTER_REGNUM);
+  bitmap_set_bit (worklist, STACK_POINTER_REGNUM);
+
+  if (frame_pointer_needed)
+    {
+      add_to_hard_reg_set (&stack_slot_access, Pmode,
+			   HARD_FRAME_POINTER_REGNUM);
+      bitmap_set_bit (worklist, HARD_FRAME_POINTER_REGNUM);
     }
+
+  /* Registers on HARD_STACK_SLOT_ACCESS always access stack.  */
+  HARD_REG_SET hard_stack_slot_access = stack_slot_access;
+
+  calculate_dominance_info (CDI_DOMINATORS);
+
+  unsigned int regno;
+
+  do
+    {
+      regno = bitmap_clear_first_set_bit (worklist);
+      ix86_find_all_reg_uses (stack_slot_access, regno, worklist);
+    }
+  while (!bitmap_empty_p (worklist));
+
+  hard_reg_set_iterator hrsi;
+  stack_access_data data;
+
+  auto_bitmap reg_dominate_bbs_known[FIRST_PSEUDO_REGISTER];
+  auto_bitmap reg_dominate_bbs[FIRST_PSEUDO_REGISTER];
+
+  data.stack_alignment = &stack_alignment;
+
+  EXECUTE_IF_SET_IN_HARD_REG_SET (stack_slot_access, 0, regno, hrsi)
+    {
+      for (df_ref ref = DF_REG_USE_CHAIN (regno);
+	   ref != NULL;
+	   ref = DF_REF_NEXT_REG (ref))
+	{
+	  if (DF_REF_IS_ARTIFICIAL (ref))
+	    continue;
+
+	  rtx_insn *insn = DF_REF_INSN (ref);
+
+	  if (!NONJUMP_INSN_P (insn))
+	    continue;
+
+	  /* Call ix86_access_stack_p only if INSN needs alignment >
+	     STACK_ALIGNMENT.  */
+	  if (ix86_need_alignment_p (insn, stack_alignment)
+	      && (TEST_HARD_REG_BIT (hard_stack_slot_access, regno)
+		  || ix86_access_stack_p (regno, BLOCK_FOR_INSN (insn),
+					  set_up_by_prologue,
+					  prologue_used,
+					  reg_dominate_bbs_known,
+					  reg_dominate_bbs)))
+	    {
+	      /* Update stack alignment if REGNO is used for stack
+		 access.  */
+	      data.reg = DF_REF_REG (ref);
+	      note_stores (insn, ix86_update_stack_alignment, &data);
+	    }
+	}
+    }
+
+  free_dominance_info (CDI_DOMINATORS);
 }
 
 /* Finalize stack_realign_needed and frame_pointer_needed flags, which
diff --git a/gcc/function.cc b/gcc/function.cc
index 2f3c6355e5e..5ade058d724 100644
--- a/gcc/function.cc
+++ b/gcc/function.cc
@@ -6091,9 +6091,6 @@ make_epilogue_seq (void)
 void
 thread_prologue_and_epilogue_insns (void)
 {
-  /* We need alias.  */
-  init_alias_analysis ();
-
   df_analyze ();
 
   /* Can't deal with multiple successors of the entry block at the
@@ -6326,9 +6323,6 @@ thread_prologue_and_epilogue_insns (void)
       df_update_entry_block_defs ();
       df_update_exit_block_uses ();
     }
-
-  /* Clean up.  */
-  end_alias_analysis ();
 }
 
 /* Reposition the prologue-end and epilogue-begin notes after
diff --git a/gcc/rtl.h b/gcc/rtl.h
index 3cb5a808da7..ac9ba94e3fb 100644
--- a/gcc/rtl.h
+++ b/gcc/rtl.h
@@ -4029,8 +4029,6 @@ extern struct target_rtl *this_target_rtl;
   (this_target_rtl->x_top_of_stack)
 #define mode_mem_attrs \
   (this_target_rtl->x_mode_mem_attrs)
-#define static_reg_base_value \
-  (this_target_rtl->x_static_reg_base_value)
 
 /* All references to certain hard regs, except those created
    by allocating pseudo regs into them (when that's possible),
diff --git a/gcc/testsuite/g++.target/i386/pr126202-1.C b/gcc/testsuite/g++.target/i386/pr126202-1.C
new file mode 100644
index 00000000000..95d463bf017
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/pr126202-1.C
@@ -0,0 +1,71 @@
+/* { dg-do compile { target pie } } */
+/* { dg-options "-O3 -std=gnu++20 -march=znver5 -fPIE" } */
+
+typedef int fixed16_16;
+struct vec2_fixed
+{
+  fixed16_16 x, z;
+} s_polygonUv[32];
+struct vec3_fixed
+{
+  fixed16_16 x, y, z;
+};
+template <typename> struct allocator_traits;
+template <typename> class allocator;
+template <typename _Tp> struct allocator_traits<allocator<_Tp>>
+{
+  using value_type = _Tp;
+  using pointer = _Tp *;
+  template <typename _Up> using rebind_alloc = allocator<_Up>;
+};
+template <typename _Alloc> struct __alloc_traits : allocator_traits<_Alloc>
+{
+  typedef allocator_traits<_Alloc> _Base_type;
+  typedef _Base_type::value_type reference;
+  template <typename _Tp> struct rebind
+  {
+    typedef typename _Base_type::rebind_alloc<_Tp> other;
+  };
+};
+template <typename _Tp, typename _Alloc> struct _Vector_base
+{
+  typedef __alloc_traits<_Alloc>::template rebind<_Tp>::other _Tp_alloc_type;
+  struct
+  {
+    __alloc_traits<_Tp_alloc_type>::pointer _M_start;
+  } _M_impl;
+};
+template <typename _Tp, typename _Alloc = allocator<_Tp>>
+struct vector : _Vector_base<_Tp, _Alloc>
+{
+  __alloc_traits<typename _Vector_base<_Tp, _Alloc>::_Tp_alloc_type>::reference
+  operator[] (int __n)
+  {
+    return *(this->_M_impl._M_start + __n);
+  }
+};
+extern int vertexCount, s_polygonIntensity_0;
+struct JmPolygon
+{
+  int *indices;
+};
+extern vector<vec3_fixed> s_verticesVS;
+extern vector<fixed16_16> s_vertexIntensity;
+extern vec3_fixed s_polygonVerticesVS[2];
+extern JmPolygon *robj3d_setupPolygon_polygon;
+void
+robj3d_setupPolygon ()
+{
+  for (int v = 0; v < vertexCount; v++)
+    s_polygonVerticesVS[v]
+        = s_verticesVS[robj3d_setupPolygon_polygon->indices[v]];
+  vec2_fixed *uv = (vec2_fixed *)robj3d_setupPolygon_polygon;
+  vec2_fixed zero{};
+  for (int v = 0; v < vertexCount; v++)
+    s_polygonUv[v] = uv[v];
+  for (int v = 0; v < vertexCount; v++)
+    s_polygonUv[v] = zero;
+  for (int v;;)
+    s_polygonIntensity_0
+        = s_vertexIntensity[robj3d_setupPolygon_polygon->indices[v]];
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr126202-1.c b/gcc/testsuite/gcc.target/i386/pr126202-1.c
new file mode 100644
index 00000000000..7a2b5b7be15
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr126202-1.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-march=x86-64 -mavx -O2 -fno-strict-overflow" } */
+
+typedef long __m128i __attribute__ ((__vector_size__ (16)));
+__m128i _mm_store_si128___B;
+typedef long __m256i __attribute__ ((__vector_size__ (32)));
+int vpx_quantize_b_avx___trans_tmp_6, vpx_quantize_b_avx_index;
+void
+_mm256_store_si256 (__m256i *__P, __m256i __A)
+{
+  *__P = __A;
+}
+void
+store_tran_low (int *b)
+{
+  *(__m128i *)b = _mm_store_si128___B;
+}
+void
+vpx_quantize_b_avx (int, long, int, int *qcoeff_ptr, int, short,
+                    short *eob_ptr)
+{
+  __m256i __trans_tmp_5 = {};
+  if (vpx_quantize_b_avx___trans_tmp_6)
+    _mm256_store_si256 ((__m256i *)(qcoeff_ptr
+				    + vpx_quantize_b_avx_index + 8),
+                        __trans_tmp_5);
+  store_tran_low (qcoeff_ptr + vpx_quantize_b_avx_index + 8);
+  *eob_ptr = 0;
+}
-- 
2.55.0

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