search for: g_merge_values

Displaying 5 results from an estimated 5 matches for "g_merge_values".

Did you mean: g_unmerge_values
2018 Sep 21
2
[GlobalISel] Legalize generic instructions that also depend on type of scalar, not only scalar size
Hi, Mips32 has 64 bit floating point instructions, while i64 instructions have to be emulated with i32 instructions. This means that G_LOAD should be custom legalized for s64 integer value, and be legal for s64 floating point value. There are also other generic instructions with the same problem: G_STORE, G_SELECT, G_EXTRACT, and G_INSERT. There are also other configurations where integer
2019 Jan 07
2
GlobalISel legalization artifact legalization
Hi, I’m trying to handle some vector operations with splitting/scalarization and keep running into similar sorts of issues which are making me question the intended function of the various legalization operations (particularly G_MERGE_VALUES/G_UNMERGE_VALUES, but also G_EXTRACT/G_INSERT and conversion instructions) and what the contract between the legalizer and selector actually is. For scalar values, things seem clearer, but I’m still confused. The AArch64 selector code seems content to allow strange sized values in the source of G_...
2020 Feb 27
2
Correct modelling of instructions with types smaller than the register class
...cussion on D75086 regarding declaring types as legal even if they are smaller than the actual register class (e.g. s16 and gpr32). We are working on a backend which only has 32 and 64-bit registers and we recently had a problem regarding exactly this where we had to declare G_UNMERGE_VALUES and G_MERGE_VALUES with a smaller type of <s32 as legal, even though we don't have a register class that matches and instruction selection implicitly sign extends them to s32. The reasoning was that for example in the case of G_UNMERGE_VALUES, the legalizer widens the source type when widening the destinat...
2020 Mar 02
2
Correct modelling of instructions with types smaller than the register class
...discussion on D75086 regarding declaring types as legal even if they are smaller than the actual register class (e.g. s16 and gpr32). We are working on a backend which only has 32 and 64-bit registers and we recently had a problem regarding exactly this where we had to declare G_UNMERGE_VALUES and G_MERGE_VALUES with a smaller type of <s32 as legal, even though we don't have a register class that matches and instruction selection implicitly sign extends them to s32. The reasoning was that for example in the case of G_UNMERGE_VALUES, the legalizer widens the source type when widening the destination...
2018 Dec 20
2
RegBankSelect complex value mappings
Hi, I’m looking at RegBankSelect’s partially implemented support for deciding to split a value between multiple registers and I’m wondering if it’s actually intended to solve the problem I’m trying to use it for. RegisterBankInfo.h has this example mapping table: /// E.g., /// Let say we have a 32-bit add and a <2 x 32-bit> vadd. We /// can expand the /// <2 x 32-bit> add into