mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-07-20 10:30:03 +00:00
fa1cf8cd68
For pattern like ((x >> C1) & Mask) << C2, DAG combiner may convert it into (x >> (C1-C2)) & (Mask << C2), which makes pattern matching of ubfx more difficult. For example: Given %shr = lshr i64 %x, 4 %and = and i64 %shr, 15 %arrayidx = getelementptr inbounds [8 x [64 x i64]]* @arr, i64 0, %i64 2, i64 %and %0 = load i64* %arrayidx With current shift folding, it takes 3 instrs to compute base address: lsr x8, x0, #1 and x8, x8, #0x78 add x8, x9, x8 If using ubfx, it only needs 2 instrs: ubfx x8, x0, #4, #4 add x8, x9, x8, lsl #3 This fixes bug 19589 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207702 91177308-0d34-0410-b5e6-96231b3b80d8 |
||
|---|---|---|
| .. | ||
| AArch64 | ||
| ARM | ||
| ARM64 | ||
| CPP | ||
| Generic | ||
| Hexagon | ||
| Inputs | ||
| Mips | ||
| MSP430 | ||
| NVPTX | ||
| PowerPC | ||
| R600 | ||
| SPARC | ||
| SystemZ | ||
| Thumb | ||
| Thumb2 | ||
| X86 | ||
| XCore | ||