Update to use the new MathExtras.h support for log2 computation.
Patch contributed by Jim Laskey!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22594 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPC32ISelSimple.cpp b/lib/Target/PowerPC/PPC32ISelSimple.cpp
index aabee95..8771db2 100644
--- a/lib/Target/PowerPC/PPC32ISelSimple.cpp
+++ b/lib/Target/PowerPC/PPC32ISelSimple.cpp
@@ -26,11 +26,35 @@
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/InstVisitor.h"
+#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/Statistic.h"
#include <vector>
using namespace llvm;
+
+// IsRunOfOnes - returns true if Val consists of one contiguous run of 1's with
+// any number of 0's on either side. the 1's are allowed to wrap from LSB to
+// MSB. so 0x000FFF0, 0x0000FFFF, and 0xFF0000FF are all runs. 0x0F0F0000 is
+// not, since all 1's are not contiguous.
+static bool IsRunOfOnes(unsigned Val, unsigned &MB, unsigned &ME) {
+ if (isShiftedMask_32(Val)) {
+ // look for the first non-zero bit
+ MB = CountLeadingZeros_32(Val);
+ // look for the first zero bit after the run of ones
+ ME = CountLeadingZeros_32((Val - 1) ^ Val);
+ return true;
+ } else if (isShiftedMask_32(Val = ~Val)) { // invert mask
+ // effectively look for the first zero bit
+ ME = CountLeadingZeros_32(Val) - 1;
+ // effectively look for the first one bit after the run of zeros
+ MB = CountLeadingZeros_32((Val - 1) ^ Val) + 1;
+ return true;
+ }
+ // no run present
+ return false;
+}
+
namespace {
/// TypeClass - Used by the PowerPC backend to group LLVM types by their basic
/// PPC Representation.
@@ -2085,73 +2109,6 @@
BuildMI(*BB, IP, Opcode, 2, DestReg).addReg(Op0r).addReg(Op1r);
}
-// ExactLog2 - This function solves for (Val == 1 << (N-1)) and returns N. It
-// returns zero when the input is not exactly a power of two.
-static unsigned ExactLog2(unsigned Val) {
- if (Val == 0 || (Val & (Val-1))) return 0;
- unsigned Count = 0;
- while (Val != 1) {
- Val >>= 1;
- ++Count;
- }
- return Count;
-}
-
-// isRunOfOnes - returns true if Val consists of one contiguous run of 1's with
-// any number of 0's on either side. the 1's are allowed to wrap from LSB to
-// MSB. so 0x000FFF0, 0x0000FFFF, and 0xFF0000FF are all runs. 0x0F0F0000 is
-// not, since all 1's are not contiguous.
-static bool isRunOfOnes(unsigned Val, unsigned &MB, unsigned &ME) {
- bool isRun = true;
- MB = 0;
- ME = 0;
-
- // look for first set bit
- int i = 0;
- for (; i < 32; i++) {
- if ((Val & (1 << (31 - i))) != 0) {
- MB = i;
- ME = i;
- break;
- }
- }
-
- // look for last set bit
- for (; i < 32; i++) {
- if ((Val & (1 << (31 - i))) == 0)
- break;
- ME = i;
- }
-
- // look for next set bit
- for (; i < 32; i++) {
- if ((Val & (1 << (31 - i))) != 0)
- break;
- }
-
- // if we exhausted all the bits, we found a match at this point for 0*1*0*
- if (i == 32)
- return true;
-
- // since we just encountered more 1's, if it doesn't wrap around to the
- // most significant bit of the word, then we did not find a match to 1*0*1* so
- // exit.
- if (MB != 0)
- return false;
-
- // look for last set bit
- for (MB = i; i < 32; i++) {
- if ((Val & (1 << (31 - i))) == 0)
- break;
- }
-
- // if we exhausted all the bits, then we found a match for 1*0*1*, otherwise,
- // the value is not a run of ones.
- if (i == 32)
- return true;
- return false;
-}
-
/// isInsertAndHalf - Helper function for emitBitfieldInsert. Returns true if
/// OpUser has one use, is used by an or instruction, and is itself an and whose
/// second operand is a constant int. Optionally, set OrI to the Or instruction
@@ -2281,7 +2238,7 @@
// succeeded in matching one of the cases for generating rlwimi. Update the
// skip lists and users of the Instruction::Or.
unsigned MB, ME;
- if (((TgtMask ^ InsMask) == 0xFFFFFFFF) && isRunOfOnes(InsMask, MB, ME)) {
+ if (((TgtMask ^ InsMask) == 0xFFFFFFFF) && IsRunOfOnes(InsMask, MB, ME)) {
SkipList.push_back(Op0User);
SkipList.push_back(Op1User);
SkipList.push_back(OptAndI);
@@ -2320,7 +2277,7 @@
if (matched == false)
return false;
- if (isRunOfOnes(Imm, MB, ME)) {
+ if (IsRunOfOnes(Imm, MB, ME)) {
unsigned SrcReg = getReg(Op, MBB, IP);
BuildMI(*MBB, IP, PPC::RLWINM, 4, DestReg).addReg(SrcReg).addImm(Rotate)
.addImm(MB).addImm(ME);
@@ -2361,7 +2318,7 @@
if (Opcode == 2 && !Op1->isNullValue()) {
unsigned MB, ME, mask = Op1->getRawValue();
- if (isRunOfOnes(mask, MB, ME)) {
+ if (IsRunOfOnes(mask, MB, ME)) {
BuildMI(*MBB, IP, PPC::RLWINM, 4, DestReg).addReg(Op0Reg).addImm(0)
.addImm(MB).addImm(ME);
return;
@@ -2582,7 +2539,9 @@
}
// If the element size is exactly a power of 2, use a shift to get it.
- if (unsigned Shift = ExactLog2(CI->getRawValue())) {
+ uint64_t C = CI->getRawValue();
+ if (isPowerOf2_64(C)) {
+ unsigned Shift = Log2_64(C);
ConstantUInt *ShiftCI = ConstantUInt::get(Type::UByteTy, Shift);
emitShiftOperation(MBB, IP, Op0, ShiftCI, true, Op0->getType(), 0, DestReg);
return;
@@ -2729,8 +2688,8 @@
return;
}
- unsigned log2V = ExactLog2(V);
- if (log2V != 0 && Ty->isSigned()) {
+ if (isPowerOf2_32(V) && Ty->isSigned()) {
+ unsigned log2V = Log2_32(V);
unsigned Op0Reg = getReg(Op0, MBB, IP);
unsigned TmpReg = makeAnotherReg(Op0->getType());