From 026d9454b1d9971061ad2e7d47c3ef4b0b96495d Mon Sep 17 00:00:00 2001
From: Patrick O'Neill <patrick@rivosinc.com>
Date: Tue, 14 Nov 2023 15:08:31 -0800
Subject: [PATCH] RISC-V: Fix ICE in non-canonical march parsing

Passing in a base extension in non-canonical order (i, e, g) causes GCC
to ICE:
xgcc: error: '-march=rv64ge': ISA string is not in canonical order. 'e'
xgcc: internal compiler error: in add, at common/config/riscv/riscv-common.cc:671
...

This is fixed by skipping to the next extension when a non-canonical
order is detected.

gcc/ChangeLog:

	* common/config/riscv/riscv-common.cc
	(riscv_subset_list::parse_std_ext): Emit an error and skip to
	the next extension when a non-canonical ordering is detected.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/arch-27.c: New test.
	* gcc.target/riscv/arch-28.c: New test.

Signed-off-by: Patrick O'Neill <patrick@rivosinc.com>
---
 gcc/common/config/riscv/riscv-common.cc  | 17 +++++++++++++----
 gcc/testsuite/gcc.target/riscv/arch-27.c |  7 +++++++
 gcc/testsuite/gcc.target/riscv/arch-28.c |  7 +++++++
 3 files changed, 27 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/riscv/arch-27.c
 create mode 100644 gcc/testsuite/gcc.target/riscv/arch-28.c

diff --git a/gcc/common/config/riscv/riscv-common.cc b/gcc/common/config/riscv/riscv-common.cc
index 526dbb7603b..5111626157b 100644
--- a/gcc/common/config/riscv/riscv-common.cc
+++ b/gcc/common/config/riscv/riscv-common.cc
@@ -1017,15 +1017,24 @@ riscv_subset_list::parse_std_ext (const char *p)
       std_ext = *p;
 
       /* Checking canonical order.  */
+      const char *prior_std_exts = std_exts;
+
       while (*std_exts && std_ext != *std_exts)
 	std_exts++;
 
       subset[0] = std_ext;
       if (std_ext != *std_exts && standard_extensions_p (subset))
-	error_at (m_loc,
-		  "%<-march=%s%>: ISA string is not in canonical order. "
-		  "%<%c%>",
-		  m_arch, *p);
+	{
+	  error_at (m_loc,
+		    "%<-march=%s%>: ISA string is not in canonical order. "
+		    "%<%c%>",
+		    m_arch, *p);
+	  /* Extension ordering is invalid.  Ignore this extension and keep
+	     searching for other issues with remaining extensions.  */
+	  std_exts = prior_std_exts;
+	  p++;
+	  continue;
+	}
 
       std_exts++;
 
diff --git a/gcc/testsuite/gcc.target/riscv/arch-27.c b/gcc/testsuite/gcc.target/riscv/arch-27.c
new file mode 100644
index 00000000000..70143b2156f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/arch-27.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64ge -mabi=lp64d" } */
+int foo()
+{
+}
+
+/* { dg-error "ISA string is not in canonical order. 'e'" "" { target *-*-* } 0 } */
diff --git a/gcc/testsuite/gcc.target/riscv/arch-28.c b/gcc/testsuite/gcc.target/riscv/arch-28.c
new file mode 100644
index 00000000000..934399a7b3a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/arch-28.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64imaefcv -mabi=lp64d" } */
+int foo()
+{
+}
+
+/* { dg-error "ISA string is not in canonical order. 'e'" "" { target *-*-* } 0 } */