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1877ec9b02
registers, and update it on entry to each function, then restore it on exit. This compiles: void func(vfloat *a, vfloat *b, vfloat *c) { *a = *b * *c + *c; } to this: _func: mfspr r2, 256 oris r6, r2, 49152 mtspr 256, r6 lvx v0, 0, r5 lvx v1, 0, r4 vmaddfp v0, v1, v0, v0 stvx v0, 0, r3 mtspr 256, r2 blr GCC produces this (which has additional stack accesses): _func: mfspr r0,256 stw r0,-4(r1) oris r0,r0,0xc000 mtspr 256,r0 lvx v0,0,r5 lvx v1,0,r4 lwz r12,-4(r1) vmaddfp v0,v0,v1,v0 stvx v0,0,r3 mtspr 256,r12 blr git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26733 91177308-0d34-0410-b5e6-96231b3b80d8 |
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.. | ||
Alpha | ||
CBackend | ||
IA64 | ||
PowerPC | ||
Skeleton | ||
Sparc | ||
SparcV8 | ||
SparcV9 | ||
X86 | ||
Makefile | ||
MRegisterInfo.cpp | ||
README.txt | ||
SubtargetFeature.cpp | ||
Target.td | ||
TargetData.cpp | ||
TargetFrameInfo.cpp | ||
TargetInstrInfo.cpp | ||
TargetMachine.cpp | ||
TargetMachineRegistry.cpp | ||
TargetSchedInfo.cpp | ||
TargetSchedule.td | ||
TargetSelectionDAG.td | ||
TargetSubtarget.cpp |
Target Independent Opportunities: ===-------------------------------------------------------------------------=== FreeBench/mason contains code like this: static p_type m0u(p_type p) { int m[]={0, 8, 1, 2, 16, 5, 13, 7, 14, 9, 3, 4, 11, 12, 15, 10, 17, 6}; p_type pu; pu.a = m[p.a]; pu.b = m[p.b]; pu.c = m[p.c]; return pu; } We currently compile this into a memcpy from a static array into 'm', then a bunch of loads from m. It would be better to avoid the memcpy and just do loads from the static array. ===-------------------------------------------------------------------------=== Get the C front-end to expand hypot(x,y) -> llvm.sqrt(x*x+y*y) when errno and precision don't matter (ffastmath). Misc/mandel will like this. :) //===---------------------------------------------------------------------===// Solve this DAG isel folding deficiency: int X, Y; void fn1(void) { X = X | (Y << 3); } compiles to fn1: movl Y, %eax shll $3, %eax orl X, %eax movl %eax, X ret The problem is the store's chain operand is not the load X but rather a TokenFactor of the load X and load Y, which prevents the folding. There are two ways to fix this: 1. The dag combiner can start using alias analysis to realize that y/x don't alias, making the store to X not dependent on the load from Y. 2. The generated isel could be made smarter in the case it can't disambiguate the pointers. Number 1 is the preferred solution. //===---------------------------------------------------------------------===// Turn this into a signed shift right in instcombine: int f(unsigned x) { return x >> 31 ? -1 : 0; } http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25600 http://gcc.gnu.org/ml/gcc-patches/2006-02/msg01492.html //===---------------------------------------------------------------------===// On targets with expensive 64-bit multiply, we could LSR this: for (i = ...; ++i) { x = 1ULL << i; into: long long tmp = 1; for (i = ...; ++i, tmp+=tmp) x = tmp; This would be a win on ppc32, but not x86 or ppc64. //===---------------------------------------------------------------------===// Shrink: (setlt (loadi32 P), 0) -> (setlt (loadi8 Phi), 0) //===---------------------------------------------------------------------===// Reassociate is missing this: int test(int X, int Y) { return (X+X+Y+Y); // (X+Y) << 1; } it needs to turn the shifts into multiplies to get it. //===---------------------------------------------------------------------===// Reassociate should turn: X*X*X*X -> t=(X*X) (t*t) to eliminate a multiply. //===---------------------------------------------------------------------===// Interesting? testcase for add/shift/mul reassoc: int bar(int x, int y) { return x*x*x+y+x*x*x*x*x*y*y*y*y; } int foo(int z, int n) { return bar(z, n) + bar(2*z, 2*n); } //===---------------------------------------------------------------------===// These two functions should generate the same code on big-endian systems: int g(int *j,int *l) { return memcmp(j,l,4); } int h(int *j, int *l) { return *j - *l; } this could be done in SelectionDAGISel.cpp, along with other special cases, for 1,2,4,8 bytes. //===---------------------------------------------------------------------===//