[Bug tree-optimization/126920] ICE in gimple_phi_arg_def_from_edge in gcc/gimpl.h

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126920

--- Comment #7 from Frank Scheiner <frank.scheiner at web dot de> ---
Indeed, also fixed for us with
r17-3357-g0ebadbad7c92133c467f7aed6f3c16a9e3b55774 :
```
root@b450m-g-p:/usr/src/ssd/torvalds-linux# ia64-linux-gcc
-Wp,-MMD,lib/zstd/compress/.zstd_lazy.o.d -nostdinc -I./arch/ia64/include
-I./arch/ia64/include/generated -I./include -I./include
-I./arch/ia64/include/uapi -I./arch/ia64/include/generated/uapi
-I./include/uapi -I./include/generated/uapi -include
./include/linux/compiler-version.h -include ./include/linux/kconfig.h -include
./include/linux/compiler_types.h -D__KERNEL__ -DHAVE_WORKING_TEXT_ALIGN
-DHAVE_MODEL_SMALL_ATTRIBUTE -DHAVE_SERIALIZE_DIRECTIVE -fshort-wchar
-funsigned-char -fno-common -fno-PIE -fno-strict-aliasing -std=gnu11
-fms-extensions -pipe -ffixed-r13 -mfixed-range=f12-f15,f32-f127
-frename-registers -fno-optimize-sibling-calls -fno-delete-null-pointer-checks
-O2 -fno-allow-store-data-races -fno-stack-protector -fomit-frame-pointer
-ftrivial-auto-var-init=zero -fzero-init-padding-bits=all
-fno-stack-clash-protection -fdiagnostics-show-context=2
-fmin-function-alignment=32 -fstrict-flex-arrays=3 -fno-strict-overflow
-fno-stack-check -fconserve-stack -fno-builtin-wcslen -Wall -Wextra -Wundef
-Werror=implicit-function-declaration -Werror=implicit-int -Werror=return-type
-Werror=strict-prototypes -Wno-format-security -Wno-trigraphs
-Wno-frame-address -Wno-address-of-packed-member -Wmissing-declarations
-Wmissing-prototypes -Wframe-larger-than=2048 -Wno-main -Wno-type-limits
-Wno-dangling-pointer -Wvla-larger-than=1 -Wno-pointer-sign
-Wcast-function-type -Wno-unterminated-string-initialization -Wno-array-bounds
-Wno-stringop-overflow -Wno-alloc-size-larger-than -Wimplicit-fallthrough=5
-Werror=date-time -Werror=incompatible-pointer-types -Werror=designated-init
-Wenum-conversion -Wunused -Wno-unused-but-set-variable
-Wno-unused-const-variable -Wno-packed-not-aligned -Wno-format-overflow
-Wno-format-truncation -Wno-stringop-truncation -Wno-override-init
-Wno-missing-field-initializers -Wno-shift-negative-value
-Wno-maybe-uninitialized -Wno-sign-compare -Wno-unused-parameter  -mconstant-gp
 -DKBUILD_MODFILE='"lib/zstd/zstd_compress"' -DKBUILD_BASENAME='"zstd_lazy"'
-DKBUILD_MODNAME='"zstd_compress"' -D__KBUILD_MODNAME=zstd_compress -c -o
lib/zstd/compress/zstd_lazy.o lib/zstd/compress/zstd_lazy.c
root@b450m-g-p:/usr/src/ssd/torvalds-linux# echo $?
0
```

Also confirmed by successfully redoing all 3 originally failing compilations
with the same compiler (gcc-17-20260816 snapshot and the above mentioned patch
on top).