[arm] PR target/89400 fix thumb1 unaligned access expansiongcc-9-branch

Armv6 has support for unaligned accesses to memory.  However, the
thumb1 code patterns were trying to use the 32-bit code constraints.
One failure mode from this was that the patterns are designed to be
compatible with conditional execution and this was then causing an
assert in the compiler.

The unaligned_loadhis pattern is only used for expanding extv, which
in turn is only enabled for systems supporting thumb2.  Given that
there is no simple expansion for a thumb1 sign-extending load (the
instruction has no immediate offset form and requires two registers in
the address) it seems simpler to just disable this for thumb1.

Fixed thusly:

        Backport from trunk:
	2019-05-03  Richard Earnshaw  <rearnsha@arm.com>

	PR target/89400
	* config/arm/arm.md (unaligned_loadsi): Add variant for thumb1.
	Restrict 'all' variant to 32-bit configurations.
	(unaligned_loadhiu): Likewise.
	(unaligned_storehi): Likewise.
	(unaligned_storesi): Likewise.
	(unaligned_loadhis): Disable when compiling for thumb1.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-9-branch@277123 138bc75d-0d04-0410-961f-82ee72b054a4

2 files changed, 58 insertions, 29 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 77d7fa94140..afa2f8df2cc 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,16 @@
+2019-10-17  Richard Earnshaw  <rearnsha@arm.com>
+
+	Backport from mainline
+	2019-05-03  Richard Earnshaw  <rearnsha@arm.com>
+
+	PR target/89400
+	* config/arm/arm.md (unaligned_loadsi): Add variant for thumb1.
+	Restrict 'all' variant to 32-bit configurations.
+	(unaligned_loadhiu): Likewise.
+	(unaligned_storehi): Likewise.
+	(unaligned_storesi): Likewise.
+	(unaligned_loadhis): Disable when compiling for thumb1.
+
 2019-10-16  Iain Sandoe  <iain@sandoe.co.uk>
 
 	Backport from mainline
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 0aecd03891c..ae582172ab9 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -4483,62 +4483,78 @@
 ; ARMv6+ unaligned load/store instructions (used for packed structure accesses).
 
 (define_insn "unaligned_loadsi"
-  [(set (match_operand:SI 0 "s_register_operand" "=l,r")
-	(unspec:SI [(match_operand:SI 1 "memory_operand" "Uw,m")]
+  [(set (match_operand:SI 0 "s_register_operand" "=l,l,r")
+	(unspec:SI [(match_operand:SI 1 "memory_operand" "m,Uw,m")]
 		   UNSPEC_UNALIGNED_LOAD))]
   "unaligned_access"
-  "ldr%?\t%0, %1\t@ unaligned"
-  [(set_attr "arch" "t2,any")
-   (set_attr "length" "2,4")
-   (set_attr "predicable" "yes")
-   (set_attr "predicable_short_it" "yes,no")
+  "@
+   ldr\t%0, %1\t@ unaligned
+   ldr%?\t%0, %1\t@ unaligned
+   ldr%?\t%0, %1\t@ unaligned"
+  [(set_attr "arch" "t1,t2,32")
+   (set_attr "length" "2,2,4")
+   (set_attr "predicable" "no,yes,yes")
+   (set_attr "predicable_short_it" "no,yes,no")
    (set_attr "type" "load_4")])
 
+;; The 16-bit Thumb1 variant of ldrsh requires two registers in the
+;; address (there's no immediate format).  That's tricky to support
+;; here and we don't really need this pattern for that case, so only
+;; enable for 32-bit ISAs.
 (define_insn "unaligned_loadhis"
   [(set (match_operand:SI 0 "s_register_operand" "=r")
 	(sign_extend:SI
 	  (unspec:HI [(match_operand:HI 1 "memory_operand" "Uh")]
 		     UNSPEC_UNALIGNED_LOAD)))]
-  "unaligned_access"
+  "unaligned_access && TARGET_32BIT"
   "ldrsh%?\t%0, %1\t@ unaligned"
   [(set_attr "predicable" "yes")
    (set_attr "type" "load_byte")])
 
 (define_insn "unaligned_loadhiu"
-  [(set (match_operand:SI 0 "s_register_operand" "=l,r")
+  [(set (match_operand:SI 0 "s_register_operand" "=l,l,r")
 	(zero_extend:SI
-	  (unspec:HI [(match_operand:HI 1 "memory_operand" "Uw,m")]
+	  (unspec:HI [(match_operand:HI 1 "memory_operand" "m,Uw,m")]
 		     UNSPEC_UNALIGNED_LOAD)))]
   "unaligned_access"
-  "ldrh%?\t%0, %1\t@ unaligned"
-  [(set_attr "arch" "t2,any")
-   (set_attr "length" "2,4")
-   (set_attr "predicable" "yes")
-   (set_attr "predicable_short_it" "yes,no")
+  "@
+   ldrh\t%0, %1\t@ unaligned
+   ldrh%?\t%0, %1\t@ unaligned
+   ldrh%?\t%0, %1\t@ unaligned"
+  [(set_attr "arch" "t1,t2,32")
+   (set_attr "length" "2,2,4")
+   (set_attr "predicable" "no,yes,yes")
+   (set_attr "predicable_short_it" "no,yes,no")
    (set_attr "type" "load_byte")])
 
 (define_insn "unaligned_storesi"
-  [(set (match_operand:SI 0 "memory_operand" "=Uw,m")
-	(unspec:SI [(match_operand:SI 1 "s_register_operand" "l,r")]
+  [(set (match_operand:SI 0 "memory_operand" "=m,Uw,m")
+	(unspec:SI [(match_operand:SI 1 "s_register_operand" "l,l,r")]
 		   UNSPEC_UNALIGNED_STORE))]
   "unaligned_access"
-  "str%?\t%1, %0\t@ unaligned"
-  [(set_attr "arch" "t2,any")
-   (set_attr "length" "2,4")
-   (set_attr "predicable" "yes")
-   (set_attr "predicable_short_it" "yes,no")
+  "@
+   str\t%1, %0\t@ unaligned
+   str%?\t%1, %0\t@ unaligned
+   str%?\t%1, %0\t@ unaligned"
+  [(set_attr "arch" "t1,t2,32")
+   (set_attr "length" "2,2,4")
+   (set_attr "predicable" "no,yes,yes")
+   (set_attr "predicable_short_it" "no,yes,no")
    (set_attr "type" "store_4")])
 
 (define_insn "unaligned_storehi"
-  [(set (match_operand:HI 0 "memory_operand" "=Uw,m")
-	(unspec:HI [(match_operand:HI 1 "s_register_operand" "l,r")]
+  [(set (match_operand:HI 0 "memory_operand" "=m,Uw,m")
+	(unspec:HI [(match_operand:HI 1 "s_register_operand" "l,l,r")]
 		   UNSPEC_UNALIGNED_STORE))]
   "unaligned_access"
-  "strh%?\t%1, %0\t@ unaligned"
-  [(set_attr "arch" "t2,any")
-   (set_attr "length" "2,4")
-   (set_attr "predicable" "yes")
-   (set_attr "predicable_short_it" "yes,no")
+  "@
+   strh\t%1, %0\t@ unaligned
+   strh%?\t%1, %0\t@ unaligned
+   strh%?\t%1, %0\t@ unaligned"
+  [(set_attr "arch" "t1,t2,32")
+   (set_attr "length" "2,2,4")
+   (set_attr "predicable" "no,yes,yes")
+   (set_attr "predicable_short_it" "no,yes,no")
    (set_attr "type" "store_4")])