--- name: testKilled tracksRegLiveness: true body: | bb.0.entry: liveins: $x3, $f1, $x5 $x3 = ADDI8 $x5, 100 STD killed $x5, $x5, 100 STFSX killed $f1, $zero8, killed $x3 BLR8 implicit $lr8, implicit $rm
llc -mtriple=powerpc64le--linux-gnu -stop-after ppc-pre-emit-peephole t.mir -o - -verify-machineinstrs
# After PowerPC Pre-Emit Peephole # Machine code for function testKill: NoPHIs, TracksLiveness, NoVRegs bb.0.entry: liveins: $f1, $x3, $x5 STD killed $x5, $x5, 100 STFS killed $f1, 100, $x5 BLR8 implicit $lr8, implicit $rm # End machine code for function testKill. *** Bad machine code: Using an undefined physical register *** - function: testKill - basic block: %bb.0 entry (0x100313d8218) - instruction: STFS killed $f1, 100, $x5 - operand 2: $x5 LLVM ERROR: Found 1 machine code errors.
PowerPC Peephole will convert ADDI8 + STFSX to STFS. But currently it does not consider about killed/dead flag, so after transformation in the above case $x5 is used after killed.