[Wasm64] Fix PostEmscripten::optimizeExceptions on invokes with an i64 argument (#6074)

In wasm64, function pointers are 64-bit like all pointers.

fixes #6073

Author: kripken

src/passes/PostEmscripten.cpp

@@ -317,7 +317,7 @@ struct PostEmscripten : public Pass {
         // The first operand is the function pointer index, which must be
         // constant if we are to optimize it statically.
         if (auto* index = curr->operands[0]->dynCast<Const>()) {
-          size_t indexValue = index->value.geti32();
+          size_t indexValue = index->value.getInteger();
           if (indexValue >= flatTable.names.size()) {
             // UB can lead to indirect calls to invalid pointers.
             return;

test/lit/passes/post-emscripten-64.wast

@@ -0,0 +1,31 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+;; RUN: wasm-opt %s --post-emscripten -all -S -o - | filecheck %s
+
+;; Test we do not error on invoke calls that take an i64 index (which is the
+;; case in wasm64). Nothing should change here.
+
+(module
+ ;; CHECK:      (type $0 (func (param i64)))
+
+ ;; CHECK:      (type $1 (func))
+
+ ;; CHECK:      (import "env" "invoke_v" (func $invoke (type $0) (param i64)))
+ (import "env" "invoke_v" (func $invoke (param i64)))
+
+ ;; CHECK:      (table $0 269 269 funcref)
+ (table $0 269 269 funcref)
+ ;; CHECK:      (elem $0 (i32.const 1))
+ (elem $0 (i32.const 1))
+
+ ;; CHECK:      (func $0 (type $1)
+ ;; CHECK-NEXT:  (call $invoke
+ ;; CHECK-NEXT:   (i64.const 42)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $0
+  (call $invoke
+   (i64.const 42)
+  )
+ )
+)
+