[backport from gcc-4.7/trunk <mikpe@it.uu.se>]

Date: Wed, 23 Mar 2011 23:52:34 +0900
From: Chung-Lin Tang <cltang at codesourcery dot com>
Subject: [patch, ARM] Fix PR46934, Thumb-1 ICE
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>

Hi, in the ARM "casesi" expand pattern, when the table base index
constant is 0x8000000, it is stored sign extended as an rtx (const_int
0xffffffff8000000) (assuming 64-bit HOST_WIDE_INT).

Subtraction by adding GEN_INT(-INTVAL(operands[1])) then creates
(const_int 0x80000000), which is not sign-extended, and fails to match
the nonmemory_operand predicate later, causing a extract_insn failure
ICE.  So the fix is to use gen_int_mode() instead of GEN_INT, which does
the needed sign-extension.

Cross-tested on QEMU without regressions, okay for trunk?

gcc/

2011-03-23  Chung-Lin Tang  <cltang@codesourcery.com>

	PR target/46934
	* config/arm/arm.md (casesi): Use the gen_int_mode() function
	to subtract lower bound instead of GEN_INT().

gcc/testsuite/

2011-03-23  Chung-Lin Tang  <cltang@codesourcery.com>

	* gcc.target/arm/pr46934.c: New.

--- gcc-4.6.0/gcc/config/arm/arm.md.~1~	2011-03-15 20:59:25.000000000 +0100
+++ gcc-4.6.0/gcc/config/arm/arm.md	2011-05-14 16:04:13.000000000 +0200
@@ -8354,7 +8354,8 @@ (define_expand "casesi"
 	rtx reg = gen_reg_rtx (SImode);
 
 	emit_insn (gen_addsi3 (reg, operands[0],
-			       GEN_INT (-INTVAL (operands[1]))));
+			       gen_int_mode (-INTVAL (operands[1]),
+			       		     SImode)));
 	operands[0] = reg;
       }
 
--- gcc-4.6.0/gcc/testsuite/gcc.target/arm/pr46934.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.6.0/gcc/testsuite/gcc.target/arm/pr46934.c	2011-05-14 16:04:13.000000000 +0200
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-march=armv5te -mthumb -Os" }  */
+/* { dg-require-effective-target arm_thumb1_ok } */
+
+int caller (unsigned int reg_type)
+{
+  switch (reg_type)
+    {
+    case 0x80000000:
+      return (int)foo();
+
+    case 0x80000003:
+      return (int) bar();
+
+    case 0x80000001:
+      return (int) baz();
+
+    case 0x80000004:
+      return (int) fooz();
+    }
+}