http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55754
Bug #: 55754
Summary: FAIL: gcc.target/arm/unsigned-extend-2.c
scan-assembler ands
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: regression
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: ktkac...@gcc.gnu.org
CC: ramana.radhakrish...@arm.com, richard.earns...@arm.com
Target: arm-none-eabi
FAIL: gcc.target/arm/unsigned-extend-2.c scan-assembler ands
FAIL: gcc.target/arm/unsigned-extend-2.c scan-assembler-not uxtb
FAIL: gcc.target/arm/unsigned-extend-2.c scan-assembler-not cmp
Bisection shows r194608 introduces the FAILs.
In particular the following snippet causes the test FAIL:
/* If *op0 is (zero_extend:SI (subreg:QI (reg:SI) 0)) and comparing
with const0_rtx, change it to (and:SI (reg:SI) (const_int 255)),
to facilitate possible combining with a cmp into 'ands'. */
- if (mode == SImode
+ if (!op0_preserve_value
+ && mode == SImode
&& GET_CODE (*op0) == ZERO_EXTEND
&& GET_CODE (XEXP (*op0, 0)) == SUBREG
&& GET_MODE (XEXP (*op0, 0)) == QImode
This change disables the transformation that the testcase is looking for.
Thanks,
Kyrill
