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8365205: C2: Optimize popcount value computation using knownbits #27075

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c83be33
8365205: C2: Optimize popcount value computation using knownbits
jbhateja Sep 3, 2025
a68fbc0
New IR test addition and review resolutions
jbhateja Sep 5, 2025
52ae6bc
Update countbitsnode.cpp
jatin-bhateja Sep 5, 2025
36ecb5d
Update src/hotspot/share/opto/countbitsnode.cpp
jatin-bhateja Sep 10, 2025
f1095b5
review resoultions
jbhateja Sep 10, 2025
9e3957d
Update TestPopCountValueTransforms.java
jatin-bhateja Sep 10, 2025
a7f9b79
Adding random bound test point
jbhateja Sep 11, 2025
278f1dc
Extending the random ranges
jbhateja Sep 15, 2025
367622b
Review comments resolutions
jbhateja Sep 19, 2025
92cf2fa
Update TestPopCountValueTransforms.java
jatin-bhateja Sep 19, 2025
e206ccc
Update countbitsnode.cpp
jatin-bhateja Sep 19, 2025
85b10e8
Review comments resolution
jbhateja Oct 4, 2025
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50 changes: 23 additions & 27 deletions test/hotspot/jtreg/compiler/intrinsics/TestPopCountValueTransforms.java
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Original file line number Diff line number Diff line change
Expand Up @@ -43,17 +43,17 @@ public class TestPopCountValueTransforms {

static final int SIZE = 4096;

static int rand_numI = G.uniformInts(0, Integer.MAX_VALUE).next();
static final int rand_bndI1 = G.uniformInts(0xF, Integer.MAX_VALUE).next();
static final int rand_bndI2 = G.uniformInts(0xFF, Integer.MAX_VALUE).next();
static final int rand_popcI1 = G.uniformInts(0, 2).next();
static final int rand_popcI2 = G.uniformInts(10, 20).next();

static long rand_numL = G.uniformLongs(0, Long.MAX_VALUE).next();
static final long rand_bndL1 = G.uniformLongs(0xFL, Long.MAX_VALUE).next();
static final long rand_bndL2 = G.uniformLongs(0xFFL, Long.MAX_VALUE).next();
static final long rand_popcL1 = G.uniformLongs(0, 3).next();
static final long rand_popcL2 = G.uniformLongs(20, 40).next();
static int rand_numI = G.uniformInts(Integer.MIN_VALUE, Integer.MAX_VALUE).next();
static final int rand_bndI1 = G.uniformInts(-0xFF, 0xFF).next();
static final int rand_bndI2 = G.uniformInts(-0xFFFFF, 0xFFFFF).next();
static final int rand_popcI1 = G.uniformInts(0, 4).next();
static final int rand_popcI2 = G.uniformInts(0, 32).next();

static long rand_numL = G.uniformLongs(Long.MIN_VALUE, Long.MAX_VALUE).next();
static final long rand_bndL1 = G.uniformLongs(-0xFFL, 0xFFL).next();
static final long rand_bndL2 = G.uniformLongs(-0xFFFFFFL, 0xFFFFFF).next();
static final long rand_popcL1 = G.uniformLongs(0, 4).next();
static final long rand_popcL2 = G.uniformLongs(0, 32).next();

@Test
@IR(counts = {IRNode.POPCOUNT_L, " 0 "})
Expand Down Expand Up @@ -147,15 +147,13 @@ public int testPopCountRandomInt() {

@Check(test = "testPopCountRandomInt")
public void checkPopCountRandomInt(int res) {
if (res == 1) {
int exp = 0;
int num = Math.clamp(rand_numI, Math.min(rand_bndI1, rand_bndI2), Math.max(rand_bndI1, rand_bndI2));
while(num != 0) {
num &= (num - 1);
exp++;
}
Verify.checkEQ(exp >= rand_popcI1 && exp < rand_popcI2, true);
int exp = 0;
int num = Math.clamp(rand_numI, Math.min(rand_bndI1, rand_bndI2), Math.max(rand_bndI1, rand_bndI2));
while(num != 0) {
num &= (num - 1);
exp++;
}
Verify.checkEQ(exp >= rand_popcI1 && exp < rand_popcI2 ? 1 : -1, res);
}

@Test
Expand All @@ -170,15 +168,13 @@ public long testPopCountRandomLong() {

@Check(test = "testPopCountRandomLong")
public void checkPopCountRandomLong(long res) {
if (res == 1) {
int exp = 0;
long num = Math.clamp(rand_numL, Math.min(rand_bndL1, rand_bndL2), Math.max(rand_bndL1, rand_bndL2));
while(num != 0) {
num &= (num - 1L);
exp++;
}
Verify.checkEQ(exp >= rand_popcL1 && exp < rand_popcL2, true);
int exp = 0;
long num = Math.clamp(rand_numL, Math.min(rand_bndL1, rand_bndL2), Math.max(rand_bndL1, rand_bndL2));
while(num != 0) {
num &= (num - 1L);
exp++;
}
Verify.checkEQ(exp >= rand_popcL1 && exp < rand_popcL2 ? 1L : -1L, res);
}

public TestPopCountValueTransforms() {
Expand Down