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am 0b5830e8: am 374ad789: Merge change 24577 into eclair 

Merge commit '0b5830e8f1d8b18afa238e5c3ac154c326bd4fb1'

* commit '0b5830e8f1d8b18afa238e5c3ac154c326bd4fb1':
  Update peephole optimizer
This commit is contained in:
Jack Palevich 2009-09-10 14:16:21 -07:00 committed by Android Git Automerger
parent 1357a2f968 0b5830e8f1
commit a95ca3888f
1 changed files with 48 additions and 11 deletions
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59
libacc/acc.cpp
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@ -730,6 +730,18 @@ class Compiler : public ErrorSink {
return rotateRight(data, rotate);
}
static bool isPowerOfTwo(size_t n) {
return (n != 0) & ((n & (n-1)) == 0);
}
static size_t log2(size_t n) {
int result = 0;
while (n >>= 1) {
result++;
}
return result;
}
class ARMCodeBuf : public ICodeBuf {
ICodeBuf* mpBase;
ErrorSink* mErrorSink;
@ -825,8 +837,9 @@ class Compiler : public ErrorSink {
// Peephole check
bool didPeep;
do {
const unsigned int opMask = 0x01e00000;
const unsigned int immediateMask = 0x00000fff;
static const unsigned int opMask = 0x01e00000;
static const unsigned int immediateMask = 0x00000fff;
static const unsigned int BMask = 0x00400000;
didPeep = false;
if (mQ.count() >= 4) {
@ -853,16 +866,25 @@ class Compiler : public ErrorSink {
}
// Load local variable
// sub r0,r11,#imm;ldr r0,[r0] ==> ldr r0, [r11,#-imm]
// sub r0,r11,#imm;ldr/ldrb r0,[r0] ==> ldr/ldrb r0, [r11,#-imm]
if (mQ.count() >= 2) {
if ((mQ[-2] & ~immediateMask) == 0xe24b0000 && // sub r0,r11,#imm
mQ[-1] == 0xe5900000) { // ldr r0, [r0]
unsigned int op = mQ[-2];
unsigned int ld = mQ[-1];
unsigned int combined = (op & immediateMask) | 0xE51B0000; // ldr r0, [r11, #-0]
mQ.popBack(2);
mQ.pushBack(combined);
didPeep = true;
if ((mQ[-2] & ~immediateMask) == 0xe24b0000) { // sub r0,r11,#imm
const unsigned int encodedImmediate = mQ[-2] & immediateMask;
const unsigned int ld = mQ[-1];
if ((ld & ~BMask) == 0xe5900000) { // ldr{b} r0, [r0]
unsigned int combined = encodedImmediate | (0xE51B0000 | (ld & BMask)); // ldr r0, [r11, #-0]
mQ.popBack(2);
mQ.pushBack(combined);
didPeep = true;
} else if (ld == 0xedd07a00) { // ldcl p10, c7, [r0, #0x000]
unsigned int decodedImmediate = decode12BitImmediate(encodedImmediate);
if (decodedImmediate <= 1020 && ((decodedImmediate & 3) == 0)) {
unsigned int combined = (decodedImmediate >> 2) | 0xed5b7a00; // ldcl p10, c7, [r11, #-0]
mQ.popBack(2);
mQ.pushBack(combined);
didPeep = true;
}
}
}
}
@ -891,6 +913,21 @@ class Compiler : public ErrorSink {
}
}
// Pointer arithmetic with a stride that is a power of two
if (mQ.count() >= 3 &&
(mQ[-3] & ~ immediateMask) == 0xe3a02000 && // mov r2, #stride
mQ[-2] == 0xe0000092 && // mul r0, r2, r0
mQ[-1] == 0xe0810000) { // add r0, r1, r0
int stride = decode12BitImmediate(mQ[-3]);
if (isPowerOfTwo(stride)) {
mQ.popBack(3);
unsigned int add = 0xe0810000 | (log2(stride) << 7); // add r0, r1, r0, LSL #log2(stride)
mQ.pushBack(add);
didPeep = true;
}
}
} while (didPeep);
#endif
}