summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--src/passes/OptimizeInstructions.cpp36
-rw-r--r--test/emcc_hello_world.fromasm36
-rw-r--r--test/emcc_hello_world.fromasm.imprecise36
-rw-r--r--test/passes/optimize-instructions.txt37
-rw-r--r--test/passes/optimize-instructions.wast47
5 files changed, 138 insertions, 54 deletions
diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
index 6dbb1b7e8..c81119f75 100644
--- a/src/passes/OptimizeInstructions.cpp
+++ b/src/passes/OptimizeInstructions.cpp
@@ -305,6 +305,24 @@ static int32_t lowBitMask(int32_t bits) {
return ret >> (32 - bits);
}
+// performs a dynCast on the fallthrough value, i.e., looks through
+// too and block fallthroughs, etc.
+template<typename T>
+T* getFallthroughDynCast(Expression* curr) {
+ if (T* ret = curr->dynCast<T>()) {
+ return ret;
+ }
+ if (auto* set = curr->dynCast<SetLocal>()) {
+ if (set->isTee()) return getFallthroughDynCast<T>(set->value);
+ } else if (auto* block = curr->dynCast<Block>()) {
+ // if no name, we can't be broken to, and then can look at the fallthrough
+ if (!block->name.is() && block->list.size() > 0) {
+ return getFallthroughDynCast<T>(block->list.back());
+ }
+ }
+ return nullptr;
+}
+
// Main pass class
struct OptimizeInstructions : public WalkerPass<PostWalker<OptimizeInstructions, UnifiedExpressionVisitor<OptimizeInstructions>>> {
bool isFunctionParallel() override { return true; }
@@ -359,11 +377,14 @@ struct OptimizeInstructions : public WalkerPass<PostWalker<OptimizeInstructions,
if (auto* ext = getAlmostSignExt(binary)) {
Index extraShifts;
auto bits = getAlmostSignExtBits(binary, extraShifts);
- auto* load = ext->dynCast<Load>();
+ auto* load = getFallthroughDynCast<Load>(ext);
// pattern match a load of 8 bits and a sign extend using a shl of 24 then shr_s of 24 as well, etc.
if (load && ((load->bytes == 1 && bits == 8) || (load->bytes == 2 && bits == 16))) {
- load->signed_ = true;
- return removeAlmostSignExt(binary);
+ // if the value falls through, we can't alter the load, as it might be captured in a tee
+ if (load->signed_ == true || load == ext) {
+ load->signed_ = true;
+ return removeAlmostSignExt(binary);
+ }
}
// if the sign-extend input cannot have a sign bit, we don't need it
if (getMaxBits(ext) + extraShifts < bits) {
@@ -405,11 +426,14 @@ struct OptimizeInstructions : public WalkerPass<PostWalker<OptimizeInstructions,
return binary->left;
}
// small loads do not need to be masted, the load itself masks
- if (auto* load = binary->left->dynCast<Load>()) {
+ if (auto* load = getFallthroughDynCast<Load>(binary->left)) {
if ((load->bytes == 1 && mask == 0xff) ||
(load->bytes == 2 && mask == 0xffff)) {
- load->signed_ = false;
- return load;
+ // if the value falls through, we can't alter the load, as it might be captured in a tee
+ if (load->signed_ == false || load == binary->left) {
+ load->signed_ = false;
+ return binary->left;
+ }
}
} else if (mask == 1 && Properties::emitsBoolean(binary->left)) {
// (bool) & 1 does not need the outer mask
diff --git a/test/emcc_hello_world.fromasm b/test/emcc_hello_world.fromasm
index e90c9c008..78f0460fa 100644
--- a/test/emcc_hello_world.fromasm
+++ b/test/emcc_hello_world.fromasm
@@ -2632,21 +2632,15 @@
(i32.lt_u
(tee_local $8
(i32.add
- (i32.shr_s
- (i32.shl
- (tee_local $11
- (i32.load8_s
- (tee_local $10
- (i32.add
- (get_local $6)
- (i32.const 1)
- )
- )
+ (tee_local $11
+ (i32.load8_s
+ (tee_local $10
+ (i32.add
+ (get_local $6)
+ (i32.const 1)
)
)
- (i32.const 24)
)
- (i32.const 24)
)
(i32.const -48)
)
@@ -2772,21 +2766,15 @@
(i32.eq
(i32.and
(tee_local $6
- (i32.shr_s
- (i32.shl
- (tee_local $1
- (i32.load8_s
- (tee_local $10
- (i32.add
- (get_local $10)
- (i32.const 1)
- )
- )
+ (tee_local $1
+ (i32.load8_s
+ (tee_local $10
+ (i32.add
+ (get_local $10)
+ (i32.const 1)
)
)
- (i32.const 24)
)
- (i32.const 24)
)
)
(i32.const -32)
diff --git a/test/emcc_hello_world.fromasm.imprecise b/test/emcc_hello_world.fromasm.imprecise
index 8a5ce0b89..ba1a50ca7 100644
--- a/test/emcc_hello_world.fromasm.imprecise
+++ b/test/emcc_hello_world.fromasm.imprecise
@@ -2575,21 +2575,15 @@
(i32.lt_u
(tee_local $8
(i32.add
- (i32.shr_s
- (i32.shl
- (tee_local $11
- (i32.load8_s
- (tee_local $10
- (i32.add
- (get_local $6)
- (i32.const 1)
- )
- )
+ (tee_local $11
+ (i32.load8_s
+ (tee_local $10
+ (i32.add
+ (get_local $6)
+ (i32.const 1)
)
)
- (i32.const 24)
)
- (i32.const 24)
)
(i32.const -48)
)
@@ -2715,21 +2709,15 @@
(i32.eq
(i32.and
(tee_local $6
- (i32.shr_s
- (i32.shl
- (tee_local $1
- (i32.load8_s
- (tee_local $10
- (i32.add
- (get_local $10)
- (i32.const 1)
- )
- )
+ (tee_local $1
+ (i32.load8_s
+ (tee_local $10
+ (i32.add
+ (get_local $10)
+ (i32.const 1)
)
)
- (i32.const 24)
)
- (i32.const 24)
)
)
(i32.const -32)
diff --git a/test/passes/optimize-instructions.txt b/test/passes/optimize-instructions.txt
index 01f1070f7..e4ab82365 100644
--- a/test/passes/optimize-instructions.txt
+++ b/test/passes/optimize-instructions.txt
@@ -1237,5 +1237,42 @@
(i32.const 256)
)
)
+ (drop
+ (tee_local $1
+ (i32.load8_s
+ (i32.const 1)
+ )
+ )
+ )
+ (drop
+ (i32.shr_s
+ (i32.shl
+ (tee_local $1
+ (i32.load8_u
+ (i32.const 1)
+ )
+ )
+ (i32.const 24)
+ )
+ (i32.const 24)
+ )
+ )
+ (drop
+ (i32.and
+ (tee_local $1
+ (i32.load8_s
+ (i32.const 1)
+ )
+ )
+ (i32.const 255)
+ )
+ )
+ (drop
+ (tee_local $1
+ (i32.load8_u
+ (i32.const 1)
+ )
+ )
+ )
)
)
diff --git a/test/passes/optimize-instructions.wast b/test/passes/optimize-instructions.wast
index 9cdec0a6c..7cfcd7a0d 100644
--- a/test/passes/optimize-instructions.wast
+++ b/test/passes/optimize-instructions.wast
@@ -1562,5 +1562,52 @@
(i32.const 16)
)
)
+ ;; through tees, we cannot alter the load sign
+ (drop
+ (i32.shr_s
+ (i32.shl
+ (tee_local $1
+ (i32.load8_s
+ (i32.const 1)
+ )
+ )
+ (i32.const 24)
+ )
+ (i32.const 24)
+ )
+ )
+ (drop
+ (i32.shr_s
+ (i32.shl
+ (tee_local $1
+ (i32.load8_u
+ (i32.const 1)
+ )
+ )
+ (i32.const 24)
+ )
+ (i32.const 24)
+ )
+ )
+ (drop
+ (i32.and
+ (tee_local $1
+ (i32.load8_s
+ (i32.const 1)
+ )
+ )
+ (i32.const 255)
+ )
+ )
+ (drop
+ (i32.and
+ (tee_local $1
+ (i32.load8_u
+ (i32.const 1)
+ )
+ )
+ (i32.const 255)
+ )
+ )
)
)
generated by cgit v1.2.3 (git 2.39.1) at 2025-08-08 12:50:16 +0000