@@ -19495,6 +19495,10 @@ thumb1_compute_save_reg_mask (void)
if (df_regs_ever_live_p (reg) && callee_saved_reg_p (reg))
mask |= 1 << reg;
+ /* Handle the frame pointer as a special case. */
+ if (frame_pointer_needed)
+ mask |= 1 << HARD_FRAME_POINTER_REGNUM;
+
if (flag_pic
&& !TARGET_SINGLE_PIC_BASE
&& arm_pic_register != INVALID_REGNUM
new file mode 100644
@@ -0,0 +1,45 @@
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+__attribute__ ((noinline, noclone)) void
+clobber_sp (void)
+{
+ __asm volatile ("" : : : "sp");
+}
+
+int
+main (void)
+{
+ int ret;
+
+ __asm volatile ("mov\tr4, #0xf4\n\t"
+ "mov\tr5, #0xf5\n\t"
+ "mov\tr6, #0xf6\n\t"
+ "mov\tr7, #0xf7\n\t"
+ "mov\tr0, #0xf8\n\t"
+ "mov\tr8, r0\n\t"
+ "mov\tr0, #0xfa\n\t"
+ "mov\tr10, r0"
+ : : : "r0", "r4", "r5", "r6", "r7", "r8", "r10");
+ clobber_sp ();
+
+ __asm volatile ("cmp\tr4, #0xf4\n\t"
+ "bne\tfail\n\t"
+ "cmp\tr5, #0xf5\n\t"
+ "bne\tfail\n\t"
+ "cmp\tr6, #0xf6\n\t"
+ "bne\tfail\n\t"
+ "cmp\tr7, #0xf7\n\t"
+ "bne\tfail\n\t"
+ "mov\tr0, r8\n\t"
+ "cmp\tr0, #0xf8\n\t"
+ "bne\tfail\n\t"
+ "mov\tr0, r10\n\t"
+ "cmp\tr0, #0xfa\n\t"
+ "bne\tfail\n\t"
+ "mov\t%0, #1\n"
+ "fail:\n\t"
+ "sub\tr0, #1"
+ : "=r" (ret) : :);
+ return ret;
+}
Hi, We have decided to backport this patch to fix callee-saved register corruption when clobbering sp to our embedded-6-branch. *** gcc/ChangeLog.arm *** PR target/77904 * config/arm/arm.c (thumb1_compute_save_reg_mask): Mark frame pointer in save register mask if it is needed. *** gcc/testsuite/ChangeLog.arm *** PR target/77904 * gcc.target/arm/pr77904.c: New test. Best regards, Thomas Ping? Best regards, Thomas On 03/11/16 16:52, Thomas Preudhomme wrote: > Hi, > > When using a callee-saved register to save the frame pointer the Thumb-1 > prologue fails to save the callee-saved register before that. For ARM and > Thumb-2 targets the frame pointer is handled as a special case but nothing is > done for Thumb-1 targets. This patch adds the same logic for Thumb-1 targets. > > ChangeLog entries are as follow: > > *** gcc/ChangeLog *** > > 2016-11-02 Thomas Preud'homme <thomas.preudhomme@arm.com> > > PR target/77904 > * config/arm/arm.c (thumb1_compute_save_reg_mask): mark frame pointer > in save register mask if it is needed. > > > *** gcc/testsuite/ChangeLog *** > > 2016-11-02 Thomas Preud'homme <thomas.preudhomme@arm.com> > > PR target/77904 > * gcc.target/arm/pr77904.c: New test. > > > Testing: Testsuite shows no regression when run with arm-none-eabi GCC > cross-compiler for Cortex-M0 target. > > Is this ok for trunk? > > Best regards, > > Thomas