| Summary: | ARM EABI violation when passing arguments to helper floating functions like __aeabi_d2iz | ||
|---|---|---|---|
| Product: | gcc | Reporter: | bin.cheng <amker.cheng> |
| Component: | target | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | mikpelinux, ramana |
| Priority: | P3 | Keywords: | ABI, wrong-code |
| Version: | 4.7.0 | ||
| Target Milestone: | 4.5.4 | ||
| Host: | Target: | arm-none-eabi | |
| Build: | Known to work: | ||
| Known to fail: | 4.5.3, 4.6.0, 4.6.1, 4.6.2, 4.7.0 | Last reconfirmed: | 2012-01-16 00:00:00 |
Confirmed This is only applicable to the 4.6 branch and trunk since support for the Cortex M4 wasn't added till 4.6. cheers Ramana Author: jye2 Date: Mon Jan 30 16:59:14 2012 New Revision: 183733 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=183733 Log: 2012-01-30 Bin Cheng <bin.cheng@arm.com> PR target/51835 * config/arm/arm.c (arm_libcall_uses_aapcs_base): Use correct ABI for __aeabi_d2iz/__aeabi_d2uiz with hard-float. testcases: PR target/51835 * gcc.target/arm/pr51835.c: New testcase. Added: trunk/gcc/testsuite/gcc.target/arm/pr51835.c Modified: trunk/gcc/ChangeLog trunk/gcc/config/arm/arm.c trunk/gcc/testsuite/ChangeLog Author: jye2 Date: Mon Jan 30 17:22:04 2012 New Revision: 183734 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=183734 Log: 2012-01-30 Bin Cheng <bin.cheng@arm.com> PR target/51835 * config/arm/arm.c (arm_libcall_uses_aapcs_base): Use correct ABI for __aeabi_d2iz/__aeabi_d2uiz with hard-float. testcases: PR target/51835 * gcc.target/arm/pr51835.c: New testcase. Added: branches/gcc-4_6-branch/gcc/testsuite/gcc.target/arm/pr51835.c Modified: branches/gcc-4_6-branch/gcc/ChangeLog branches/gcc-4_6-branch/gcc/config/arm/arm.c branches/gcc-4_6-branch/gcc/testsuite/ChangeLog (In reply to comment #2) > This is only applicable to the 4.6 branch and trunk since support for the > Cortex M4 wasn't added till 4.6. > > cheers > Ramana Maybe the Cortex M4 wasn't added until 4.6, but the other options are permitted by 4.5 and I can easily get 4.5 to produce wrong-looking code. With -O2 -mfloat-abi=hard -mfpu=fpv4-sp-d16 -march=armv7-a -marm I see the following code generation difference between 4.5 and 4.6: @@ -22,8 +22,9 @@ @ frame_needed = 0, uses_anonymous_args = 0 stmfd sp!, {r3, lr} bl __aeabi_f2d + fmrrd r0, r1, d0 bl __aeabi_d2iz ldmfd sp!, {r3, pc} .size func, .-func - .ident "GCC: (GNU) 4.5.4 20120126 (prerelease)" + .ident "GCC: (GNU) 4.6.3 20120203 (prerelease)" .section .note.GNU-stack,"",%progbits Backporting r183734 from 4.6 to 4.5 makes 4.5 generate the same code as 4.6, i.e., with the fmrrd between the two calls. (In reply to comment #5) > (In reply to comment #2) > > This is only applicable to the 4.6 branch and trunk since support for the > > Cortex M4 wasn't added till 4.6. > > > > cheers > > Ramana > > Maybe the Cortex M4 wasn't added until 4.6, but the other options are permitted > by 4.5 and I can easily get 4.5 to produce wrong-looking code. With -O2 > -mfloat-abi=hard -mfpu=fpv4-sp-d16 -march=armv7-a -marm I see the following > code generation difference between 4.5 and 4.6: > > @@ -22,8 +22,9 @@ > @ frame_needed = 0, uses_anonymous_args = 0 > stmfd sp!, {r3, lr} > bl __aeabi_f2d > + fmrrd r0, r1, d0 > bl __aeabi_d2iz > ldmfd sp!, {r3, pc} > .size func, .-func > - .ident "GCC: (GNU) 4.5.4 20120126 (prerelease)" > + .ident "GCC: (GNU) 4.6.3 20120203 (prerelease)" > .section .note.GNU-stack,"",%progbits > > Backporting r183734 from 4.6 to 4.5 makes 4.5 generate the same code as 4.6, > i.e., with the fmrrd between the two calls. beside this patch, Julian Brown's patch r174803 is necessary too. For now, 1, arguments for both __aeabi_f2d and __aeabi_d2iz are wrong in 4.5; 2, arguments for __aeabi_f2d is wrong in 4.6 To solve this, have to: 1, backport r183734 and r174803 to 4.5; 2, backport r174803 to 4.6; Author: amker Date: Fri Feb 10 03:14:40 2012 New Revision: 184082 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=184082 Log: Backport from mainline. 2012-01-30 Bin Cheng <bin.cheng@arm.com> PR target/51835 * config/arm/arm.c (arm_libcall_uses_aapcs_base): Use correct ABI for __aeabi_d2iz/__aeabi_d2uiz with hard-float. Backport from mainline. 2012-01-30 Bin Cheng <bin.cheng@arm.com> PR target/51835 * gcc.target/arm/pr51835.c: New testcase. Added: branches/ARM/embedded-4_6-branch/gcc/testsuite/gcc.target/arm/pr51835.c Modified: branches/ARM/embedded-4_6-branch/gcc/ChangeLog.arm branches/ARM/embedded-4_6-branch/gcc/config/arm/arm.c branches/ARM/embedded-4_6-branch/gcc/testsuite/ChangeLog.arm Author: amker Date: Tue Feb 14 07:42:41 2012 New Revision: 184197 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=184197 Log: Backport from mainline. 2012-01-30 Bin Cheng <bin.cheng@arm.com> PR target/51835 * config/arm/arm.c (arm_libcall_uses_aapcs_base): Use correct ABI for __aeabi_d2iz/__aeabi_d2uiz with hard-float. 2011-06-08 Julian Brown <julian@codesourcery.com> * config/arm/arm.c (arm_libcall_uses_aapcs_base): Use correct ABI for double-precision helper functions in hard-float mode if only single-precision arithmetic is supported in hardware. Added: branches/gcc-4_5-branch/gcc/testsuite/gcc.target/arm/pr51835.c Modified: branches/gcc-4_5-branch/gcc/ChangeLog branches/gcc-4_5-branch/gcc/config/arm/arm.c branches/gcc-4_5-branch/gcc/testsuite/ChangeLog Fixed I think now on all release branches where affected and trunk. |
For following program int func(float f) { double d = (double)f; return (int)d; } compile it with following command: $ arm-none-eabi-gcc -O2 -mthumb -mcpu=cortex-m4 -mfloat-abi=hard -mfpu=fpv4-sp-d16 -S test.c -o test.S the generated assembly code is: ----------------------------------------------- fun: @ args = 0, pretend = 0, frame = 0 @ frame_needed = 0, uses_anonymous_args = 0 push {r3, lr} fmrs r0, s0 bl __aeabi_f2d fmdrr d0, r0, r1 bl __aeabi_d2iz pop {r3, pc} .size fun, .-fun The argument of __aeabi_d2iz is passed in fp register, While ARM RTABI document says that such functions should use the soft-float ABI, even when -mfloat-abi=hard is specified. The problem at least exists on trunk and 4.6 branch. I am working a patch and will send it for review later.