fallback: legalize: G

fallback: legalize: G_SHL <8 x s8>

Run:	explore-bc8218b282-20261015-075519
Kind:	fallback
Category:	legalize: G_SHL <8 x s8>
Occurrences:	24 in 22 configs, 7 test files
Snippet from:	rvp-simd-64.ll @test_pslli_b via llvm-extract
Config:	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
Local check:	reproduces at bc8218b282
Compiler Explorer:	not uploaded (over --godbolt-limit or disabled)

Snippet:

define <8 x i8> @test_pslli_b(<8 x i8> %a) {
  %res = shl <8 x i8> %a, splat (i8 2)
  ret <8 x i8> %res
}

Reproduce:

llc -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %3:_(<8 x s8>) = G_SHL %0:_, %1:_(<8 x s8>) (in function: test_pslli_b)
warning: Instruction selection used fallback path for test_pslli_b

Occurrences (24):

Input	Function	Config
rvp-simd-64.ll	test_pslli_b	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-simd-64.ll	test_psll_bs	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-simd-64.ll	test_psll_bs_mask	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
calling-conv-ilp32f-ilp32d-common.9a3475688b.ll (mutant of calling-conv-ilp32f-ilp32d-common.ll)	callee_float_in_fpr_exhausted_gprs	`-mtriple=riscv32 -verify-machineinstrs -mattr=+f -target-abi ilp32f`
calling-conv-ilp32f-ilp32d-common.a508fdeddd.ll (mutant of calling-conv-ilp32f-ilp32d-common.ll)	callee_float_in_fpr_exhausted_gprs	`-mtriple=riscv32 -verify-machineinstrs -mattr=+d -target-abi ilp32d`
shadow-stack-frame-opts.408422eb63.ll (mutant of shadow-stack-frame-opts.ll)	caller_sw_fp	`-mtriple=riscv32 -mattr=+zimop,+xqccmp`
shadow-stack-frame-opts.4d07abf23d.ll (mutant of shadow-stack-frame-opts.ll)	caller_sw_fp	`-mtriple=riscv32 -mattr=+zimop,+zcmp`
shadow-stack-frame-opts.4e19e52d5c.ll (mutant of shadow-stack-frame-opts.ll)	caller_sw_fp	`-mtriple=riscv64 -mattr=+zimop,+zcmp,+save-restore`
shadow-stack-frame-opts.9b656229d1.ll (mutant of shadow-stack-frame-opts.ll)	caller_sw_fp	`-mtriple=riscv64 -mattr=+zimop`
shadow-stack-frame-opts.9de2cdf034.ll (mutant of shadow-stack-frame-opts.ll)	caller_sw_fp	`-mtriple=riscv32 -mattr=+zimop`
shadow-stack-frame-opts.a47de32bd2.ll (mutant of shadow-stack-frame-opts.ll)	caller_sw_fp	`-mtriple=riscv64 -mattr=+zimop,+zcmp`
shadow-stack-frame-opts.c8f8c85d48.ll (mutant of shadow-stack-frame-opts.ll)	caller_sw_fp	`-mtriple=riscv64 -mattr=+zimop,+save-restore`
shadow-stack-frame-opts.c98ed8e50d.ll (mutant of shadow-stack-frame-opts.ll)	caller_sw_fp	`-mtriple=riscv32 -mattr=+zimop,+save-restore`
shadow-stack-frame-opts.dbcfbb5e5d.ll (mutant of shadow-stack-frame-opts.ll)	caller_sw_fp	`-mtriple=riscv32 -mattr=+zimop,+zcmp,+save-restore`
shadow-stack-frame-opts.dd050c1294.ll (mutant of shadow-stack-frame-opts.ll)	caller_sw_fp	`-mtriple=riscv64 -mattr=+zimop,+xqccmp`
shift-amount-mod.a6ae42165c.ll (mutant of shift-amount-mod.ll)	lshr_by_complemented_32	`-mtriple=riscv32 -verify-machineinstrs`
shift-amount-mod.ceea003e5b.ll (mutant of shift-amount-mod.ll)	lshr_by_complemented_32	`-mtriple=riscv64 -verify-machineinstrs`
shl-cttz.034bc3ce9a.ll (mutant of shl-cttz.ll)	shl_cttz_i16	`-mtriple=riscv64 -mattr=+m,+zbb`
shl-cttz.2dd939a117.ll (mutant of shl-cttz.ll)	shl_cttz_i16	`-mtriple=riscv64 -mattr=+m`
shl-cttz.64509e41c0.ll (mutant of shl-cttz.ll)	shl_cttz_i16	`-mtriple=riscv32 -mattr=+m`
shl-cttz.777c6474e3.ll (mutant of shl-cttz.ll)	shl_cttz_i16	`-mtriple=riscv32 -mattr=+m,+zbb`
ucmp.c87bd820de.ll (mutant of ucmp.ll)	ucmp.8.32	`-mtriple=riscv32`
ucmp.fd2d5e3f48.ll (mutant of ucmp.ll)	ucmp.8.32	`-mtriple=riscv64`
xqcisls-merge-base-offset-shladd.d06752d43d.ll (mutant of xqcisls-merge-base-offset-shladd.ll)	load_scaled_i8	`-mtriple=riscv32 -mattr=+xqcili,+xqcisls,+zba,+xqciac -verify-machineinstrs`

Generated 2026-10-15 08:05 UTC.