search for: isnotnegativeusingshift

...veUsingCmp(short x) { return x > -1; } Currently, we will canonicalize these to the shift form (but you could argue that is backwards). Alive proof for logical equivalence: https://rise4fun.com/Alive/uGH If we disable the instcombine for this, we would have IR like this: define signext i16 @isNotNegativeUsingShift(i16 signext %x) { %signbit = lshr i16 %x, 15 %r = xor i16 %signbit, 1 ret i16 %r } define signext i16 @isNotNegativeUsingCmp(i16 signext %x) { %cmp = icmp sgt i16 %x, -1 %r = zext i1 %cmp to i16 ret i16 %r } And compile that for MSP430: $ ./llc -o - -mtriple=msp430 shift.ll isNotNegat...

...} > > Currently, we will canonicalize these to the shift form (but you could > argue that is backwards). > Alive proof for logical equivalence: > https://rise4fun.com/Alive/uGH > > If we disable the instcombine for this, we would have IR like this: > > define signext i16 @isNotNegativeUsingShift(i16 signext %x) { > %signbit = lshr i16 %x, 15 > %r = xor i16 %signbit, 1 > ret i16 %r > } > > define signext i16 @isNotNegativeUsingCmp(i16 signext %x) { > %cmp = icmp sgt i16 %x, -1 > %r = zext i1 %cmp to i16 > ret i16 %r > } > > And compile that fo...

On Wed, Nov 13, 2019 at 12:26 PM Joan Lluch via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Hi All, > > In relation to the subject of this message I got my first round of patches successfully reviewed and committed. As a matter of reference, they are the following: > > https://reviews.llvm.org/D69116 > https://reviews.llvm.org/D69120 >