The basic idea to this is that a) having a single canonical type makes CSE easier, and b) many of our transforms are inconsistent about which types we end up with based on visit order.
I'm restricting this to constants as for non-constants, we'd have to decide whether the simplicity was worth extra instructions. For constants, there are no extra instructions.
We chose the canonical type as i64 arbitrarily. We might consider changing this to something else in the future if we have cause.
Differential Revision: https://reviews.llvm.org/D115387
This reorders existing transforms to put demanded elements last. The reasoning here is that when we have an example which can be scalarized or handled via demanded bits, we should prefer scalarization as that doesn't require dropping flags on arithmetic instructions.
This doesn't show major changes in the tests today, but once I add support for fast math flags to dropPoisonGeneratingFlags this becomes glaringly obvious.
Differential Revision: https://reviews.llvm.org/D115394
As it's causing some bot failures (and per request from kbarton).
This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.
llvm-svn: 358546
There's a mismatch internally about how we are handling these patterns.
We count loads as cheapToScalarize(), but then we don't actually
scalarize them, so that can leave extra instructions compared to where
we started when scalarizing other ops. If it's cheapToScalarize, then
we should be scalarizing.
llvm-svn: 349560
Extracting from a splat constant is always handled by InstSimplify.
Move the test for this from InstCombine to InstSimplify to make
sure that stays true.
llvm-svn: 348423
