fallback: legalize: G_INTRINSIC_W_SIDE

fallback: legalize: G_INTRINSIC_W_SIDE_EFFECTS

Run:	explore-04ca53e65f-20261014-114124
Kind:	fallback
Category:	legalize: G_INTRINSIC_W_SIDE_EFFECTS
Occurrences:	29 in 6 configs, 4 test files
Snippet from:	riscv-zihintpause.ll @test_pause via llvm-extract
Config:	`-mtriple=riscv32 -verify-machineinstrs`
Local check:	reproduces at 04ca53e65f
Compiler Explorer:	not uploaded (over --godbolt-limit or disabled)

Snippet:

define void @test_pause() {
  call void @llvm.riscv.pause()
  ret void
}

; Function Attrs: nocallback nofree nosync nounwind willreturn
declare void @llvm.riscv.pause() #0

attributes #0 = { nocallback nofree nosync nounwind willreturn }

Reproduce:

llc -mtriple=riscv32 -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv32 -verify-machineinstrs -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: G_INTRINSIC_W_SIDE_EFFECTS intrinsic(@llvm.riscv.pause) (in function: test_pause)
warning: Instruction selection used fallback path for test_pause

Occurrences (29):

Input	Function	Config
riscv-zihintpause.ll	test_pause	`-mtriple=riscv32 -verify-machineinstrs`
riscv-zihintpause.ll	test_pause	`-mtriple=riscv64 -mattr=+zihintpause -verify-machineinstrs`
riscv-zihintpause.ll	test_pause	`-mtriple=riscv64 -verify-machineinstrs`
rv64-stackmap-nops.ll	test_shadow_optimization	`-mtriple=riscv64`
rv64-stackmap-nops.ll	test_shadow_optimization	`-mtriple=riscv64 -mattr=+c`
rv64-stackmap.ll	needsStackRealignment	`-mtriple=riscv64`
xmips-exectl.ll	test_mips_pause	`-mtriple=riscv64 -mcpu=mips-p8700 -O3 -verify-machineinstrs`
xmips-exectl.ll	test_mips_ehb	`-mtriple=riscv64 -mcpu=mips-p8700 -O3 -verify-machineinstrs`
xmips-exectl.ll	test_mips_ihb	`-mtriple=riscv64 -mcpu=mips-p8700 -O3 -verify-machineinstrs`
riscv-zihintpause.08b17bbd72.ll (mutant of riscv-zihintpause.ll)	test_pause	`-mtriple=riscv64 -verify-machineinstrs`
riscv-zihintpause.2e5d6fe0d1.ll (mutant of riscv-zihintpause.ll)	test_pause	`-mtriple=riscv64 -verify-machineinstrs`
riscv-zihintpause.324b14ce10.ll (mutant of riscv-zihintpause.ll)	test_pause	`-mtriple=riscv32 -verify-machineinstrs`
riscv-zihintpause.41b73a4426.ll (mutant of riscv-zihintpause.ll)	test_pause	`-mtriple=riscv64 -mattr=+zihintpause -verify-machineinstrs`
riscv-zihintpause.5ea6cb1de8.ll (mutant of riscv-zihintpause.ll)	test_pause	`-mtriple=riscv32 -verify-machineinstrs`
riscv-zihintpause.d583f46ce0.ll (mutant of riscv-zihintpause.ll)	test_pause	`-mtriple=riscv32 -verify-machineinstrs`
riscv-zihintpause.e8d573f1a4.ll (mutant of riscv-zihintpause.ll)	test_pause	`-mtriple=riscv64 -mattr=+zihintpause -verify-machineinstrs`
riscv-zihintpause.e9b0c88b79.ll (mutant of riscv-zihintpause.ll)	test_pause	`-mtriple=riscv64 -mattr=+zihintpause -verify-machineinstrs`
riscv-zihintpause.f11803e1ca.ll (mutant of riscv-zihintpause.ll)	test_pause	`-mtriple=riscv64 -verify-machineinstrs`
rv64-stackmap-nops.060a7bbc0f.ll (mutant of rv64-stackmap-nops.ll)	test_shadow_optimization	`-mtriple=riscv64`
rv64-stackmap-nops.6db5d074ad.ll (mutant of rv64-stackmap-nops.ll)	test_shadow_optimization	`-mtriple=riscv64 -mattr=+c`
rv64-stackmap-nops.8923fcc512.ll (mutant of rv64-stackmap-nops.ll)	test_shadow_optimization	`-mtriple=riscv64 -mattr=+c`
rv64-stackmap-nops.9fc17fffe5.ll (mutant of rv64-stackmap-nops.ll)	test_shadow_optimization	`-mtriple=riscv64 -mattr=+c`
rv64-stackmap-nops.ad2dbc1734.ll (mutant of rv64-stackmap-nops.ll)	test_shadow_optimization	`-mtriple=riscv64`
rv64-stackmap-nops.e392d1d623.ll (mutant of rv64-stackmap-nops.ll)	test_shadow_optimization	`-mtriple=riscv64`
xmips-exectl.051f00a522.ll (mutant of xmips-exectl.ll)	test_mips_pause	`-mtriple=riscv64 -mcpu=mips-p8700 -O3 -verify-machineinstrs`
xmips-exectl.556c994e2a.ll (mutant of xmips-exectl.ll)	test_mips_ehb	`-mtriple=riscv64 -mcpu=mips-p8700 -O3 -verify-machineinstrs`
xmips-exectl.a36e1e08d1.ll (mutant of xmips-exectl.ll)	test_mips_pause	`-mtriple=riscv64 -mcpu=mips-p8700 -O3 -verify-machineinstrs`
xmips-exectl.c4d637fc2f.ll (mutant of xmips-exectl.ll)	test_mips_ihb	`-mtriple=riscv64 -mcpu=mips-p8700 -O3 -verify-machineinstrs`
xmips-exectl.e9b5e8c2ec.ll (mutant of xmips-exectl.ll)	test_mips_pause	`-mtriple=riscv64 -mcpu=mips-p8700 -O3 -verify-machineinstrs`

Generated 2026-10-15 08:05 UTC.