With commit r15-1579-g792f97b44ffc5e6a967292b3747fd835e99396e7 "Add a late-combine pass [PR106594]", I see on powerpc64le-unknown-linux-gnu a number of "relocation truncated to fit: R_PPC64_TOC16 against `.rodata.cst4'" etc. with (default) '-flate-combine-instructions':

    [-PASS:-]{+FAIL:+} gcc.dg/pr91734.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} gcc.dg/pr91734.c [-execution test-]{+compilation failed to produce executable+}

    /tmp/ccOWP7Yx.o: in function `f2':
    pr91734.c:(.text+0x38): relocation truncated to fit: R_PPC64_TOC16 against `.rodata.cst4'
    /tmp/ccOWP7Yx.o: in function `f3':
    pr91734.c:(.text+0x68): relocation truncated to fit: R_PPC64_TOC16 against `.rodata.cst4'
    /tmp/ccOWP7Yx.o: in function `f4':
    pr91734.c:(.text+0x98): relocation truncated to fit: R_PPC64_TOC16 against `.rodata.cst4'+4
    /tmp/ccOWP7Yx.o: in function `f5':
    pr91734.c:(.text+0xc8): relocation truncated to fit: R_PPC64_TOC16 against `.rodata.cst4'+8
    /tmp/ccOWP7Yx.o: in function `f6':
    pr91734.c:(.text+0xf8): relocation truncated to fit: R_PPC64_TOC16 against `.rodata.cst4'+c
    /tmp/ccOWP7Yx.o: in function `f7':
    pr91734.c:(.text+0x128): relocation truncated to fit: R_PPC64_TOC16 against `.rodata.cst4'+10
    /tmp/ccOWP7Yx.o: in function `f8':
    pr91734.c:(.text+0x158): relocation truncated to fit: R_PPC64_TOC16 against `.rodata.cst4'+14
    /tmp/ccOWP7Yx.o: in function `f9':
    pr91734.c:(.text+0x188): relocation truncated to fit: R_PPC64_TOC16 against `.rodata.cst4'+18
    /tmp/ccOWP7Yx.o: in function `f10':
    pr91734.c:(.text+0x1b8): relocation truncated to fit: R_PPC64_TOC16 against `.rodata.cst4'+1c
    collect2: error: ld returned 1 exit status

This is with the Debian GNU/Linux 12 (bookworm) binutils 2.40-2 package.  (..., in case that's where the problem is...)

Similarly:

    [-PASS:-]{+FAIL:+} gcc.dg/sinatan-1.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} gcc.dg/sinatan-1.c [-execution test-]{+compilation failed to produce executable+}

    [-PASS:-]{+FAIL:+} gcc.dg/ipa/inline-8.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} gcc.dg/ipa/inline-8.c [-execution test-]{+compilation failed to produce executable+}

..., and (roughly) all 'gcc.dg/vect/tsvc/[...]' test cases that don't use '-flto'.

                    === gcc Summary ===
    
    # of expected passes            [-179982-]{+179673+}
    # of unexpected failures        [-127-]{+282+}
    # of unexpected successes       20
    # of expected failures          1612
    {+# of unresolved testcases     154+}
    # of unsupported tests          4394

Additionally:

    [-PASS:-]{+FAIL:+} libgomp.c/simd-math-1.c (test for excess errors)
    [-PASS:-]{+UNRESOLVED:+} libgomp.c/simd-math-1.c [-execution test-]{+compilation failed to produce executable+}


I see a number of recent <gcc-testresults@gcc.gnu.org> emails by Bill Seurer that contain a similar set of new FAILs, so putting you in CC here.