http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48990
Summary: MIPS wrong code error with -O1 Product: gcc Version: 4.5.3 Status: UNCONFIRMED Severity: major Priority: P3 Component: target AssignedTo: unassig...@gcc.gnu.org ReportedBy: pkon...@gcc.gnu.org Created attachment 24241 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24241 preprocessed file (trimmed a bit) that reproduces the bug The attached file compiles wrong code with -march=xlr -msoft-float -mabi=n32 -O1. It compiles correctly with -O2. The error shows up in basic block 3: the branch (beql $2,$0,$L10) has a li $4,32 in its delay slot. That clobbers $4 (A0) in the no-branch case, and A0 is still needed a few lines below. The bug is also present in GCC 4.5.1 In looking at the debug dumps, I see the problem introduced in the "mach" pass -- that pass builds a sequence insn for the branch and the load. I'll try 4.6.0 next.