Hi,
This patch detects the pattern for pointer substraction in the front-end
AST and uses EXACT_DIV_EXPR rather than TRUNC_DIV_EXPR.
Bootstrapped and regression tested on x86_64-linux-gnu with multilib
configurations -m32/-mx32. Committed to mainline.
Regards
Iain
---
gcc/d/ChangeLog:
PR d/96429
* expr.cc (ExprVisitor::visit (BinExp*)): Use EXACT_DIV_EXPR for
pointer diff expressions.
gcc/testsuite/ChangeLog:
PR d/96429
* gdc.dg/pr96429.d: New test.
---
gcc/d/expr.cc | 12 ++++++++++++
gcc/testsuite/gdc.dg/pr96429.d | 26 ++++++++++++++++++++++++++
2 files changed, 38 insertions(+)
create mode 100644 gcc/testsuite/gdc.dg/pr96429.d
diff --git a/gcc/d/expr.cc b/gcc/d/expr.cc
index 20ab49d7b8c..ac3d4aaa171 100644
--- a/gcc/d/expr.cc
+++ b/gcc/d/expr.cc
@@ -620,6 +620,18 @@ public:
break;
case TOKdiv:
+ /* Determine if the div expression is a lowered pointer diff operation.
+ The front-end rewrites `(p1 - p2)' into `(p1 - p2) / stride'. */
+ if (MinExp *me = e->e1->isMinExp ())
+ {
+ if (me->e1->type->ty == Tpointer && me->e2->type->ty == Tpointer
+ && e->e2->op == TOKint64)
+ {
+ code = EXACT_DIV_EXPR;
+ break;
+ }
+ }
+
code = e->e1->type->isintegral ()
? TRUNC_DIV_EXPR : RDIV_EXPR;
break;
diff --git a/gcc/testsuite/gdc.dg/pr96429.d b/gcc/testsuite/gdc.dg/pr96429.d
new file mode 100644
index 00000000000..af096e26b5a
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/pr96429.d
@@ -0,0 +1,26 @@
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96429
+// { dg-do compile }
+// { dg-options "-fdump-tree-original" }
+ptrdiff_t subbyte(byte* bp1, byte* bp2)
+{
+ // { dg-final { scan-tree-dump "bp1 - bp2;" "original" } }
+ return bp1 - bp2;
+}
+
+ptrdiff_t subshort(short* sp1, short* sp2)
+{
+ // { dg-final { scan-tree-dump "\\\(sp1 - sp2\\\) /\\\[ex\\\] 2;"
"original" } }
+ return sp1 - sp2;
+}
+
+ptrdiff_t subint(int* ip1, int* ip2)
+{
+ // { dg-final { scan-tree-dump "\\\(ip1 - ip2\\\) /\\\[ex\\\] 4;"
"original" } }
+ return ip1 - ip2;
+}
+
+ptrdiff_t sublong(long* lp1, long* lp2)
+{
+ // { dg-final { scan-tree-dump "\\\(lp1 - lp2\\\) /\\\[ex\\\] 8;"
"original" } }
+ return lp1 - lp2;
+}
--
2.25.1
