From ab753318793b22b219946265cfc78933201311da Mon Sep 17 00:00:00 2001
From: Walter Bright <walter@walterbright.com>
Date: Sun, 29 Dec 2024 23:52:39 -0800
Subject: [PATCH] fix #20621 Comparing addresses of rvalue reference parameters
 not correct

---
 compiler/src/dmd/backend/inliner.d | 15 ++++++++++++++-
 compiler/src/dmd/constfold.d       | 13 ++++++++++++-
 compiler/src/dmd/e2ir.d            |  4 ++--
 compiler/test/runnable/rvalue1.d   |  2 ++
 4 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/compiler/src/dmd/backend/inliner.d b/compiler/src/dmd/backend/inliner.d
index cf24050e4b3b..e4bac8fa56f6 100644
--- a/compiler/src/dmd/backend/inliner.d
+++ b/compiler/src/dmd/backend/inliner.d
@@ -516,7 +516,20 @@ private elem* initializeParamsWithArgs(elem* eargs, SYMIDX sistart, SYMIDX siend
         {
             if (log) printf("detected slice with %s\n", s.Sident.ptr);
             auto s2 = nextSymbol(si);
-            if (!s2) { symbol_print(*s); elem_print(e); assert(0); }
+            if (!s2)
+            {
+		for (size_t m = args.length; m; --m)
+		{
+		    elem* ex = args[m - 1];
+		    printf("arg[%d]\n", cast(int) m);
+		    elem_print(ex);
+		}
+
+                printf("function: %s\n", funcsym_p.Sident.ptr);
+		printf("szs: %d sze: %d\n", cast(int)szs, cast(int)sze);
+                printf("detected slice with %s\n", s.Sident.ptr);
+                symbol_print(*s); elem_print(e); assert(0);
+            }
             assert(szs == type_size(s2.Stype));
             const ty = s.Stype.Tty;
 
diff --git a/compiler/src/dmd/constfold.d b/compiler/src/dmd/constfold.d
index 1578ef770a09..9d5aa96416b5 100644
--- a/compiler/src/dmd/constfold.d
+++ b/compiler/src/dmd/constfold.d
@@ -806,6 +806,7 @@ UnionExp Equal(EXP op, const ref Loc loc, Type type, Expression e1, Expression e
 
 UnionExp Identity(EXP op, const ref Loc loc, Type type, Expression e1, Expression e2)
 {
+    //printf("Identity %s %s\n", e1.toChars(), e2.toChars());
     UnionExp ue = void;
     int cmp;
     if (e1.op == EXP.null_)
@@ -820,7 +821,17 @@ UnionExp Identity(EXP op, const ref Loc loc, Type type, Expression e1, Expressio
     {
         SymOffExp es1 = e1.isSymOffExp();
         SymOffExp es2 = e2.isSymOffExp();
-        cmp = (es1.var == es2.var && es1.offset == es2.offset);
+        cmp = es1.offset == es2.offset;
+        if (cmp)
+        {
+            cmp = es1.var == es2.var;
+            if (!cmp && (es1.var.isParameter() || es2.var.isParameter()))
+            {
+                // because of ref's, they may still be the same, we cannot tell
+                cantExp(ue);
+                return ue;
+            }
+        }
     }
     else
     {
diff --git a/compiler/src/dmd/e2ir.d b/compiler/src/dmd/e2ir.d
index e120df28d3a7..b6d0c25ad75a 100644
--- a/compiler/src/dmd/e2ir.d
+++ b/compiler/src/dmd/e2ir.d
@@ -103,7 +103,7 @@ bool ISX64REF(Declaration var)
 
     if (var.isParameter())
     {
-        if (target.os == Target.OS.Windows && target.isX86_64)
+        if (target.os == Target.OS.Windows /*&& target.isX86_64*/)
         {
             /* Use Microsoft C++ ABI
              * https://docs.microsoft.com/en-us/cpp/build/x64-calling-convention?view=msvc-170#parameter-passing
@@ -126,7 +126,7 @@ bool ISX64REF(Declaration var)
  */
 bool ISX64REF(ref IRState irs, Expression exp)
 {
-    if (irs.target.os == Target.OS.Windows && irs.target.isX86_64)
+    if (irs.target.os == Target.OS.Windows /*&& irs.target.isX86_64*/)
     {
         return exp.type.size(Loc.initial) > registerSize
                || (exp.type.isTypeStruct() && exp.type.isTypeStruct().sym.hasCopyConstruction());
diff --git a/compiler/test/runnable/rvalue1.d b/compiler/test/runnable/rvalue1.d
index 07ea4270b881..f8134f718a9f 100644
--- a/compiler/test/runnable/rvalue1.d
+++ b/compiler/test/runnable/rvalue1.d
@@ -55,6 +55,8 @@ struct S4
 {
     void* p;
 
+    this(ref S4) { }
+
     this(S4 s)
     {
         assert(&s is &x); // confirm the rvalue reference