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TODO: * gpr0 allocation * implement do-loop -> bdnz transform * implement powerpc-64 for darwin * use stfiwx in float->int * be able to combine sequences like the following into 2 instructions: lis r2, ha16(l2__ZTV4Cell) la r2, lo16(l2__ZTV4Cell)(r2) addi r2, r2, 8 * Teach LLVM how to codegen this: unsigned short foo(float a) { return a; } as: _foo: fctiwz f0,f1 stfd f0,-8(r1) lhz r3,-2(r1) blr not: _foo: fctiwz f0, f1 stfd f0, -8(r1) lwz r2, -4(r1) rlwinm r3, r2, 0, 16, 31 blr * Support 'update' load/store instructions. These are cracked on the G5, but are still a codesize win. * Add a custom legalizer for the GlobalAddress node, to move the funky darwin stub stuff from the instruction selector to the legalizer (exposing low-level operations to the dag for optzn. For example, we want to codegen this: int A = 0; void B() { A++; } as: lis r9,ha16(_A) lwz r2,lo16(_A)(r9) addi r2,r2,1 stw r2,lo16(_A)(r9) not: lis r2, ha16(_A) lwz r2, lo16(_A)(r2) addi r2, r2, 1 lis r3, ha16(_A) stw r2, lo16(_A)(r3) * should hint to the branch select pass that it doesn't need to print the second unconditional branch, so we don't end up with things like: b .LBBl42__2E_expand_function_8_674 ; loopentry.24 b .LBBl42__2E_expand_function_8_42 ; NewDefault b .LBBl42__2E_expand_function_8_42 ; NewDefault ===-------------------------------------------------------------------------=== * Codegen this: void test2(int X) { if (X == 0x12345678) bar(); } as: xoris r0,r3,0x1234 cmpwi cr0,r0,0x5678 beq cr0,L6 not: lis r2, 4660 ori r2, r2, 22136 cmpw cr0, r3, r2 bne .LBB_test2_2 ===-------------------------------------------------------------------------=== Lump the constant pool for each function into ONE pic object, and reference pieces of it as offsets from the start. For functions like this (contrived to have lots of constants obviously): double X(double Y) { return (Y*1.23 + 4.512)*2.34 + 14.38; } We generate: _X: lis r2, ha16(.CPI_X_0) lfd f0, lo16(.CPI_X_0)(r2) lis r2, ha16(.CPI_X_1) lfd f2, lo16(.CPI_X_1)(r2) fmadd f0, f1, f0, f2 lis r2, ha16(.CPI_X_2) lfd f1, lo16(.CPI_X_2)(r2) lis r2, ha16(.CPI_X_3) lfd f2, lo16(.CPI_X_3)(r2) fmadd f1, f0, f1, f2 blr It would be better to materialize .CPI_X into a register, then use immediates off of the register to avoid the lis's. This is even more important in PIC mode. ===-------------------------------------------------------------------------===