PR target/106877: Robustify reg-stack to malformed asm.

This patch resolves PR target/106877 an ICE-on-invalid inline-asm
regression.  An innocent upstream change means that the test case
from PR inline-asm/84683 now hits a different assert in reg-stack.cc's
move_for_stack_reg.  Fixed by duplicating Jakub's solution to PR 84683
https://gcc.gnu.org/pipermail/gcc-patches/2018-March/495193.html at
this second (similar) gcc_assert.

2022-09-13  Roger Sayle  <roger@nextmovesoftware.com>

gcc/ChangeLog
	PR target/106877
	* reg-stack.cc (move_for_stack_reg): Check for any_malformed_asm
	in gcc_assert.

gcc/testsuite/ChangeLog
	PR target/106877
	* g++.dg/ext/pr106877.C: New test case.

diff --git a/gcc/reg-stack.cc b/gcc/reg-stack.cc
index fd032501ad9c9c0e48e0aa06051a5fb660a5ded1..95e0e614e468002101500128bea81dd0f93d18f5 100644 (file)
--- a/gcc/reg-stack.cc
+++ b/gcc/reg-stack.cc
@@ -1073,7 +1073,8 @@ move_for_stack_reg (rtx_insn *insn, stack_ptr regstack, rtx pat)
              break;
 
          /* The destination must be dead, or life analysis is borked.  */
-         gcc_assert (get_hard_regnum (regstack, dest) < FIRST_STACK_REG);
+         gcc_assert (get_hard_regnum (regstack, dest) < FIRST_STACK_REG
+                     || any_malformed_asm);
 
          /* If the source is not live, this is yet another case of
             uninitialized variables.  Load up a NaN instead.  */

diff --git a/gcc/testsuite/g++.dg/ext/pr106877.C b/gcc/testsuite/g++.dg/ext/pr106877.C
new file mode 100644 (file)
index 0000000..6bffed9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/pr106877.C
@@ -0,0 +1,13 @@
+// PR target/106877
+// { dg-do compile { target i?86-*-* x86_64-*-* } }
+// { dg-options "-O1 -m16 -mtune=sandybridge -flive-range-shrinkage -fno-dce" }
+
+void
+foo (float b, double c)
+{
+  for (int e = 0; e < 2; e++)
+    {
+      asm volatile ("" : "+f" (c));    // { dg-error "must specify a single register" }
+      asm ("" : "+rm" (c = b));
+    }
+}