On Thu, 24 Feb 2022 14:13:47 GMT, Jatin Bhateja <jbhat...@openjdk.org> wrote:
>> Vamsi Parasa has updated the pull request incrementally with one additional >> commit since the last revision: >> >> fix 32bit build issues > > src/hotspot/cpu/x86/c2_MacroAssembler_x86.cpp line 4408: > >> 4406: jmp(done); >> 4407: bind(neg_divisor_fastpath); >> 4408: // Fastpath for divisor < 0: > > How about checking if divisor is +ve or -ve constant and non-constant > dividend in identity routine and setting a flag in IR node, which can be used > to either emit fast / slow path in a new instruction selection pattern. It > will save emitting redundant instructions. Thanks for suggesting the enhancement. This enhancement will be implemented as a part of https://bugs.openjdk.java.net/browse/JDK-8282365 > src/hotspot/share/opto/divnode.cpp line 881: > >> 879: return (phase->type( in(2) )->higher_equal(TypeLong::ONE)) ? in(1) : >> this; >> 880: } >> 881: >> //------------------------------Value------------------------------------------ > > Ideal transform to replace unsigned divide by cheaper logical right shift > instruction if divisor is POW will be useful. Thanks for suggesting the enhancement. This enhancement will be implemented as a part of https://bugs.openjdk.java.net/browse/JDK-8282365 > src/hotspot/share/opto/divnode.cpp line 897: > >> 895: >> 896: // Either input is BOTTOM ==> the result is the local BOTTOM >> 897: const Type *bot = bottom_type(); > > Can we add constant folding handling when both dividend and divisor are > constants. Thanks for suggesting the enhancement. This enhancement will be implemented as a part of https://bugs.openjdk.java.net/browse/JDK-8282365 ------------- PR: https://git.openjdk.java.net/jdk/pull/7572
